Captain America: Why everyone wants to be on Cee Lo Green's team

In a Star waggons trailer parked on Warner Brothers' Los Angeles studio complex, as Christina Aguilera preens next door, Cee Lo Green and I are studying his entirely naked and not-insubstantial stomach. Specifically, we are looking at some of the singer's myriad tattoos.

There's his grandmother's name rippling across the upper swells of his belly. In the cleavage between his man-boobs lies a squished angel. "I discovered that Tommy Lee has the same angel," the 37-year-old from Atlanta, Georgia, says of the Mötley Crüe rocker. As we talk, this teen-gang-enforcer-turned-underground-rap-icon-turned-overground-pop-star is packing his diamond necklaces into individual Ziploc plastic baggies.

Other inkings pay homage to Green's first group, the rap posse Goodie Mob, and to his star sign, Gemini – a yin and yang design is splayed across his meaty right forearm. There are Oriental characters on his back, and on the wrinkled nape below his shaved head. By his left eye there is the faint outline of a small cross. k

Does he have any idea how many tattoos he has? He doesn't. "You know," he reflects in the soft, soulful voice which, via international smash "Forget You" (née viral video sensation "Fuck You"), has helped him to album sales of almost half a million in the past six months in the UK alone, "it's kinda turning out to be just one tattoo. It's just a collage, if you will. A mosaic. I don't think I'm done. Although I haven't gone under the needle for a while. But I'm pretty sure there will be a couple more things in my life I wanna commit to skin in a very formal way."

This summer, the divorced father of three – and grandfather of one – may be enjoying a couple of experiences worthy of the tattooist's art. In the UK, he headlined Glastonbury's West Holts stage last weekend, up against U2 on the main stage – an appropriate billing for the man who won Best International Male at this year's Brits. Always one to put on a show, Green performed in a puffy red ensemble covered in spikes and chains. He looked like a satanic tomato.

In the US, meanwhile, he is the star of The Voice, a new weekly music talent show. It's been an unexpected ratings hit on the NBC network. Alongside fellow coaches (not judges) Aguilera, Maroon 5 singer Adam Levine and country singer Blake Shelton, Green has been dispensing professional wisdom to a purposefully ragtag group of wannabe singers. The first-round auditions were conducted "blind", with the coaches sitting with their backs to the hopefuls. The Voice was all about the voice, see?

Thus he finds himself coaching a chunky, gay Asian-American named Nakia ("My brother from another mother," as Green calls him), and a small, fiery lesbian Latina, Vicci Martinez. One of "Team Christina" is Beverly McClellan who, judging by her stagewear, appears to be a shaven-headed Romulan pirate. Team Blake includes petite 16-year-old Xenia, who seems utterly petrified at Shelton's suggestion that she's "representing an entire generation" – a heavy burden even if you weren't having to do this via a cover of a song by middle-of-the-road Irish soul(ish) band The Script.

Compared with the overly polished commercial juggernaut that is American Idol, The Voice is refreshingly wonky. And next to the puffy grandstanding, simpering weepiness and faux argy-bargy practised by the X Factor judges, the upstart show's pro-muso mentors are a fairly credible and very watchable alternative. But Cee Lo Green is the star. Resplendent on screen in a crisp-white Adidas tracksuit, glinting diamond necklaces, chunkily bejewelled Artica watch and sunglasses permanently strapped to his bowling-ball dome, he radiates groovily cartoon-like charisma. The Voice has made him a celebrity in the US – a particularly gratifying development for the singer, as he says the American wing of his record label was "indifferent" to his career; in fact, it was the British who signed and developed him as a solo artist. And for this assiduous ladies' man – the title of his current album The Lady Killer is not meant ironically – there are benefits.

"I gotta say that recently women have been cosying up to me just a bit more," he grins his big grin. Nor is he switching on an act for the TV cameras. "I'm pretty convincing. It's not a façade or a charade that I put up. It's me."

The Voice is the reason I find myself in his mobile dressing-room on a baking-hot LA afternoon, studying Green's flesh and watching as a make-up artist dispenses powders and puffs. "I don't get the full treatment like Christina does," he says. "I just get a few touch-ups here and there. They gotta get some of that hard living off me. So we can continue to make it look easy."

I ask Mrs Make-Up if that's true. She nods. "Just on his forehead and underneath the eyes, nothing much else – he has amazing skin. There's really not much to do."

Cee Lo Green smiles at this. He's been moisturising for this moment his whole life. Hip-hop, soul, R&B, the dark pop he made as half of Gnarls Barkley, the brighter, more fun stuff that's on The Lady Killer – none of the genres he's dabbled in have been enough to contain his ambition or enthusiasm, nor satisfy his healthy ego. "I think they would consider me the wild card among the judges," he will say. "The renaissance man, if you will. Because I'm probably more informed about pop, R&B and country than they are about alternative music – which is me. That's my edge."

Green has recently been supporting Rihanna on her North American tour. A good gig? "Um," he begins. "I've had a few stellar television performances recently. And although I'm enjoying the Rihanna tour, I must say – maybe not for the audience, cos they are a new audience, so I'm out to acquire them as well – but it's a little underwhelming for me. Because I don't get the opportunity to be as fabulous as I would like, and pull out all of the stops. And give people my speciality of old-fashioned showmanship." Indeed, a few days after our encounter, Green will pull out of his remaining commitments on the Rihanna tour, saying he had too much on his plate right now.

However The Voice, and the spotlight it brings him, is right up his freeway. Some of his fellow judges might seem diminished by appearing on a reality TV show. Both Aguilera and Levine have suffered from declining album sales recently, and there's a whiff of PR desperation about their participation. But larger-than-life, bigger-than-Jesus, all-round and just very round entertainer Cee Lo Green is enhanced by it.

And now, it seems, he's coming our way. The BBC recently won a fierce battle among British broadcasters to buy the Voice format for the UK. With the upcoming seasons of The X Factor in some turmoil on both sides of the Atlantic – in the US, Simon Cowell's launch of the show has been hobbled by CherylGate; in the UK, is Gary Barlow really a fit replacement for Cowell? – the way could be clear for The Voice to clean up. In his dressing-room before showtime, I ask Green: "Have you been offered a coaching gig on the British Voice?"

"I have."

"Have you?"

"Yeah."

"Are you gonna take it?

"I think so," he grins.

I ask if anyone else from the US show will be joining him.

"I'm not sure. And maybe I'm speaking a bit prematurely, but I plan to take it – we just have to work out a schedule that is not completely overbearing. But I think if they do it right we will have concluded with [The Voice in America] and I will be totally free to do it."

What can Simon Cowell learn from him, and from The Voice? "Um, actually, Simon had a bit of the foresight that I wish my label had," Green replies. "He actually invited me to do The X Factor first, in the UK – he wanted me to take over his seat. This was around the time that both of these options were being tossed about. We just didn't get back to each other in a timely fashion. And The Voice were just a bit more adamant about the commitment – and committing to me. So," he chuckles, "here we are."

He's come a long way. Cee Lo Green was born Thomas Callaway. Before he became immersed in music with friends such as the future members of OutKast, in his teens he acted as the muscle for Atlanta gangs. In an effort to jolt some discipline into his life, he was enrolled in a military school.

His preacher father had died of a heart attack when he was two. In his mid-teens, his mother, also an ordained minister, was involved in a car crash. It left her quadriplegic, and she died two years later. Some of the pain of those familial traumas made their way into the lyrics he wrote for Gnarls Barkley, the duo he formed with producer Danger Mouse. Their deathless 2006 hit "Crazy", for all its musical zip, features lyrics reflecting Green's psychological turmoil.

Around the time he and Danger Mouse recorded Gnarls Barkley's albums St Elsewhere (2006) and The Odd Couple (2008), "I was definitely going through a tumultuous time with one lady in particular – my ex-wife. I was going through a divorce and our home was being divided. And I'm always divided as a person, being a Gemini.

"So I had a lot of mixed emotions. But I have to remain and sustain – I couldn't allow it to drive me over the edge," Green continues in a rolling, florid speaking style that suggests his parents' profession may have had some impact on him. "Danger Mouse's music kinda resembles that controlled chaos. And I was experiencing that internally. For lack of a better term, I listened to it and thought, 'This guy's miserable. And so am I at the moment.' And at that time both our miseries needed a little company. So we were alone together."

He doesn't discount a third Gnarls Barkley album. But emotionally and musically, he has moved on.

"honestly, cee lo reminds me of someone who's a little Elton John-ish," says Mark Burnett, executive producer of The Voice. He is the undisputed king of American reality TV, and he's come a long way too. Burnett was born in Essex and served in the Falklands War before pitching up in LA and entirely reinventing himself. The original Donald Trump-led version of The Apprentice is his baby. If anyone knows about creating TV phenomena, it's Burnett.

"Cee Lo is the black hip-hop Liberace," continues this consummate TV salesman. "He's got it all going on. I'd seen him on TV on Saturday Night Live, and Lorne Michaels, who has run that show for 30 years and is a genius, he told me that Cee Lo was really great in the comedy pieces. He told me, 'He's more than just a singer. He's a real talent.' He's been around for ages but I knew that in a show like this he'd be perfect – Cee Lo is one of the voices of the moment, responsible for 'Forget You', one of the biggest songs in the world right now."

Burnett's team chose another of his huge hits, "Crazy", as The Voice's curtain-raiser: all the judges performed it together in the first episode. "It was a little awkward to begin with," says Green of the four-way sing-song, a man who speaks blunt truths in a soft voice.

"He's also very funny and personable," adds Burnett, "and he really comes to life [on camera]. It was a great choice for me. I knew he was gonna be epic."

It's 6pm: showtime. Season one of The Voice is reaching its climax. Tonight is the first live programme in the series, and it opens with Maroon 5 performing a song called "Move Like Jagger". The 1,100-strong audience clap and cheer wildly (at the off-camera warm-up man's repeated behest). Midway through the song, Christina Aguilera totters on in 10-inch Manolos, mic in hand, platinum-blonde Babs Windsor hair and boobs piled high. You can see her larynx move more than you can her rock-firm chest. In his judge's chair, Green jiggles appreciatively.

Two hours later it's all over bar the massively lucrative telephone voting and the huge Twitter and Facebook traffic that have made The Voice a social-media sensation. The show had climaxed with Team Cee Lo's Vicci Martinez performing Florence and the Machine's Dog Days Are Over accompanied by three taiko and six okedo drummers. It was the evening's best spectacle by a mile.

Afterwards, Green rides the short distance to the dressing-rooms in a golf buggy. He grins and waves at us from the back.

Outside the trailers, Mark Burnett waits to say thanks to his ratings-thumping judges. I ask him if he thinks Green – who is reportedly paid $75,000 per show – will make a good judge on the UK's version of The Voice. "Dunno how he's gonna have any time for that when he's doing this one!" he shoots back. It seems that plans are afoot for another Voice US outing this autumn, presumably in an attempt to steal some of Cowell's Stateside X Factor thunder.

As I go back into Green's trailer for a post-mortem chat, his manager follows me in. He's heard what the singer had told me earlier about The Voice UK. "The subject of The Voice in London – just to clarify: we have not had an official offer or anything like that. It's just that Cee Lo is big over there, it seems like it'd be a cool thought."

Green gives me his best innocent face. "Didn't I make that clear earlier?" he says. "Not really," I say.

"So I'm making it clear now!" his manager booms. "Because I don't want it to be a Cee Lo quote. Cos we're dealing with the Goodie Mob show..." It seems there's an idea floating around for a "fish-out-of-water" documentary following the "whimsical adventures" of Green and his long-dormant hometown hip-hop posse as they "hit" London. "And I don't want you saying that to make the BBC think, 'Oh, he's doing that too.' It'll mess up our whole deal. So," he says to me, "let everybody know: we have not been officially offered it! It was something that they brought up – 'Hey, that would be cool if you could do both.'"

His manager exits. Green blithely continues towelling off. So he got overexcited. So what? So might you if your 2011 had lift-off with a fancy-dress performance of "Forget You" at the Grammy Awards with Gwyneth Paltrow and some Muppets and now – halfway through the year – was being rocket-powered by the summer's hit American TV show.

His 10-year-old son Kingston, he says, has just arrived in town, along with his two daughters – they're biologically his ex-wife's children, but he adopted them when they were married. One recently gave birth. Kingston would be coming to the next day's live Voice show, but wouldn't be accompanying dad to Glastonbury – he doesn't have a passport. "But if we do pick up on this Voice show [in the UK], I'm gonna bring him out. He's a fine young lad," he beams with paternal pride, "he is."

Tonight there's an aftershow party at Adam Levine's house. Green plans to attend. He invites me to come along and promises that, a few drinks in, he'll tell me "the truth". He's partial to "liquor and ladies. I think I deserve a bit of both tonight," he grins. "But not too much of either one cos I have my kids in town. It's cutey time with the family."

Does he feel weird being a 37-year-old grandpa? As if.

"How I overcome it is by just thinking of myself as the coolest, hippest, freshest grandad you ever met."

Cee Lo Green's latest single, "I Want You (Hold on to Love)", is out tomorrow on Radiculture/Elektra