Justin Timberlake, Earls Court, London<br></br>Razorlight, Roadhouse, Manchester

'Come on, make some noise!" says Justin Timberlake, in possibly the most redundant request in showbiz history. "EEEEEE!!!" says London. If it seems a little superfluous to be requesting hysteria when you are self-evidently the cause of it, then it is only because in a JT show, these things aren't left to chance. Before he's even appeared, while his dancers are still warming up the crowd, a daisy-cutter-sized pyrotechnic explosion sends a mushroom cloud of glitter high into the air, ensuring that by the time he slinks on to mime "Rock Your Body" - if he isn't actually lip-synching, then he's at least ad-libbing over his own record - your heart is racing (if your hormones weren't already).

2003 was an amazing year for Justin Timberlake. We know this because he tells us. "2003 was an amazing year for me," he says. This comes at the end of a slightly icky stage-managed interval during which he stands for almost five minutes without uttering a syllable, accepting wave after wave of hosannas and ticker-tape, looking humbled and tearful, before finally launching into a long gratitude speech.

But by any standards, he's right. JT's ubiquity is staggering. Flick through the cable music channels at random, and if it isn't the other Justin (Hawkins), it's Trousersnake. The manner in which he's achieved it is interesting. In the Eighties, there was an accepted, carefully-mapped route for former boy band members: it was to recant, repent, abandon bubblegum pop, grow stubble, and appease the old heads by writing proper, mature music.

We do things differently now. Why abandon pop, when you can have so much fun making even better pop than your Svengalis and producers ever allowed you to? If George Michael was the exemplar of the old way, then Justin Timberlake is the epitome of the new school, hooking up with studio gods The Neptunes to reinvent himself as a surveyor of super-cool, state- of-the-art, impossible-to-dislike pop.

He may sound a lot like Jacko - another boy band refugee - but the visual grammar couldn't be more different. His first outfit of the night is a pair of comfy grey Vans, white jeans and a flannel shirt, which he casts off to reveal a T-shirt, with a long-sleeved top underneath. A mis-matched mix of casual clothing, as though he's just nipped out for a pint of milk.

Or, more likely, a Big Mac. It was the late great Bill Hicks who stated that any musician who accepts corporate sponsorship no longer has the right to call themselves an artist. "I'm Lovin It" banners are all around, and even the labels inside the collars on the merch stall bear the golden arches. This makes me feel a little ill (not the first time McDonald's have managed that) and, while the withdrawal of my custom won't bring down the JT empire, it put me off buying one.

It probably doesn't bother the vast majority of peons in the hall. It probably doesn't bother Justin himself. But perhaps it should. The sight of a pop star cajoling 10,000 people into singing an advert for a global corporation - which Timberlake does, staggeringly, when he actually performs the McDonald's song - is one of the most sinister I have witnessed at a concert.

And it's utterly unnecessary when he has songs of the calibre of "Girlfriend", "Let's Take A Ride", and "Like I Love You" (the moment when he says "drums", and the drums come in, is sublime). "Senorita" audibly brings it home to you just how overwhelmingly female (like, duh) this crowd is: the ladies' chant is noticeably louder than the fellas'. It's a realisation which is strengthened when he re-emerges after a costume change, and the deafening screams seem to derive from the realisation that for the last 30 seconds, Justin has been frantically hopping around in nothing but socks and boxers. "Cry Me A River" is the finest revenge tragedy in recent pop memory (and that stalker video still has the power to shock). Last time I saw Timberlake perform it, he cavorted pointedly with a Britney clone. Not this time. Maybe he's over her at last.

JT may be the second biggest thing to come from Memphis Tennessee, but unlike Presley, he was never po' white trash. Timberlake was never street: he's avenue. He knows, we know, he knows we know. And this self-awareness is central to his charm, and is one reason why, despite the fast food-flogging overkill, I can't help but like the guy.

The tour de force is the section during which Timberlake rises above our heads on a fire brigade-style cherry picker, and does his human beatbox routine, using his mouth to perform uncanny simulations of vinyl speeding up and slowing down. It instantly makes up for his earlier lip-synching by flip-reversing the situation: at the start of the show, a machine was imitating him. At the end, he's imitating a machine. Utterly brilliant.

On a smaller scale, Razorlight - one of the most talked-about new bands in Britain - seem capable of provoking Timberlake-style reactions. Just when I was jotting down the observation that none of them are exactly drop-dead gorgeous, singer Johnny Borrell climbs up on a monitor wedge, and the screams suggest that someone disagrees with me.

At first sight, it's difficult to see what the fuss is about. With his wavy grown-out bob and open-necked shirt, Londoner Borrell is an unlikely sex god, as are longhaired Swedish bassist Carl Dalemo and receding guitarist (and fellow Swede) Bjorn Agren. (Drummer Christian Smith-Pancorvo is invisible from my vantage point). But their anti-fashion look, untouched by the hand of a stylist, is possibly a statement in itself (reminiscent of The Undertones' defiant shabbiness). Musically, too, Razorlight's appeal is sometimes elusive. Borrell has complained about constant press comparisons to The Strokes, but Razorlight's finest moments come when they approximate a similar steely shudder to their more famous New York counterparts (as they do on "Rip It Up", their best known song, and set-opener).

The rest of the time, this is often thin gruel, reminiscent of some of the lesser Herberts from the New Wave of New Wave, or The Jam before they got good: Razorlight actually have a song called "In The City", and at the end of another song, they play the intro to "Eton Rifles" (as a knowing nod, I trust, and not a barefaced steal). Derivativeness is the curse of young guitar bands.

Still, the last time I had this "they're not ready yet" feeling about a band, it was The Libertines (and they didn't do too badly). And of course, The Jam did get good...

s.price@independent.co.uk

Justin Timberlake: National Indoor Arena, Birmingham (0121 780 4133), tonight and tomorrow; Telewest Arena, Newcastle-upon-Tyne (0870 707 8000), Wed & Thur; MEN Arena, Manchester (0870 190 8000), Sat. Razorlight: Bar Academy, Birmingham (0121 262 3000), tonight; Freebutt, Brighton (01273 603974), Wed; Barfly Club, Cardiff (029 2066 7658), Thur; The Louisiana, Bristol (0117 926 5978), Fri