Paul Whitehouse: Me, famous? With my reputation?

Tomorrow evening, a second series begins of the BBC drama Happiness, starring Paul Whitehouse as Danny Spencer, a narcissistic minor celebrity in the throes of a mid-life crisis. Danny is the creator and voice of a famous animated bear, and can't quite come to grips with the fact that his alter ego is far more celebrated than he is. It's a cracking premise for a drama, and indeed series one, after a slow start, deservedly built up a devoted following. I am looking forward to talking to Whitehouse about it, and about how far he has come since I first met him, a few weeks before The Fast Show aired, when he, like Danny, operated in the long shadow cast by his comedy partner, in his case Harry Enfield.

But first, in a suite in the Langham Hotel in London hired by the BBC, he asks whether I mind if he makes a phone call to his friend, the comedian Johnny Vegas, who also appears in Happiness, to congratulate him on his wedding. Vegas has his mobile switched off. Whitehouse listens to the message, cackles with laughter, and offers his good wishes mixed with some good-natured abuse. He then gives me not a good but a perfect impersonation of Vegas's raspy message. "Hi, it's Johnny, fuck off... unless it's Steven Spielberg, in which case, mate, I'll get back to you as soon as possible."

Whitehouse, it is generally acknowledged, has talent to burn, as an originator of comic ideas, and as a writer, but his true genius lies in his ability to impersonate both those who exist, such as Vegas, and those who don't, such as The Fast Show's lugubrious Irish gamekeeper Ted, and the unintelligible, inebriated QC, Rowley Birkin.

Danny Spencer is the first character he has played not to require a job of impersonation, which was at first disconcerting for Whitehouse's many fans, and suspicion inevitably arose that he was simply playing a heightened version of himself. It's a fatuous and at the same time irresistible assumption – after all, both men are in showbiz, and both are contemplating middle-life on their own, Danny having been widowed, Whitehouse having separated from his wife, Fiona. We'll come back to that. But first I ask Whitehouse, who is 44 and finally beginning to look his age, whether his first straight acting role indicates a syndrome common among fortysomething comedians. Is he the latest clown who yearns to play Hamlet?

He laughs. "No, it's quite the opposite. When I was playing Hamlet I was thinking how much I wanted to put a silly wig on and show my arse. That's why we did a Fast Show tour [which played to packed houses for two months and concluded a few weeks ago]. I'm glad I was manoeuvred into doing the live show. At first I thought it would be folly...

"I've never used that word in an interview before. Monumental folly. They go together, don't they, 'monumental' and 'folly'? Anyway, I had to be coerced. But if we were still doing The Fast Show on television people would say, 'Why the hell are you still doing that?' You've got to try something new and risk opprobrium. But you won't see me debuting at Glyndebourne."

He utters the word "Glyndebourne" with mock-pomposity, although as his mother was an opera singer, a working-class woman from the Rhondda Valley who became an understudy at Covent Garden, it cannot be that he thinks opera poncey. Maybe he's just putting me off taking him too seriously. Unlike Danny, Whitehouse is not neurotic, but if he has a neurosis, it's the fear of being taken seriously.

Consequently, it is difficult to engage him on the similarities between him and Danny, at least as regards their status as single men. He won't, understandably, talk about his estranged wife and their children (he and Fiona have two daughters, Molly and Sophie). But he concedes that he is not quite as vain as Danny. "And he's more insular, although I think I'm a bit more insular as I get older. I'm not as inept with women as he is... Mind you, that's debatable."

I ask him where the idea for the series came from. "Charlie [Higson, co-creator of The Fast Show and Ralph to his Ted] mentioned that his brother had an idea of a funny job for someone, the voice of a popular character, which seemed like a useful tool for someone with a mangled ego. His creation is very famous, and he hankers after that fame himself.

"I also remember Dave [Cummings, co-writer of Happiness] saying about the third series of The Fast Show that you could tell it was a series written by three blokes staring down the barrel of 40. That seemed like a good starting point, to look at all those issues you don't want to confront, like death, children, divorce, alcoholism, marriage... some friends of mine have started what they call the Misery Club. They just drink and bemoan failed relationships."

Whitehouse too has a failed relationship to bemoan, yet seems so eternally chirpy that it is hard to imagine him staring disconsolately into the bottom of a pint glass. I guess he must, though?

"Well, I don't get depressed, but there have certainly been moments in life when I've been really miserable."

How does his misery manifest itself?

"Wind."

We both laugh. It is a typical Whitehouse answer, just as there was a danger of things getting serious.

"Actually, I'm not being entirely flippant. While we were filming I did think I'd pulled a muscle in my stomach, and the doctor said it was stress-related wind. I do get stressed, and suffer from sleeplessness, about living up to expectations. I can get anxious about anything, but I can also let it go."

He pauses, realising he's getting serious again.

"The black dog of despair I've seen once or twice but it is not my constant companion," he adds.

There are, it seems pretty clear, more differences between Whitehouse and Danny than there are similarities. For one thing, Danny craves a great deal more fame, while there have been times when Whitehouse, former plasterer and council health officer, has craved a great deal less. He has had his share, around the time of his marriage break-up especially, of long lenses pointing at his house. "People say it goes with the territory, but I don't see why it should. Having them come up to your doorstep when you're with your kids is not pleasant, but I get an easy ride compared with some.

"On the whole, I quite like my level of fame. And I really like my job. Financially it's great, and it involves a lot of writing, so it's creative. Fame on its own is such a pointless, shallow thing. But people in the street are very nice to me. Some think that it must be a pain in the arse, people coming up and doing your catchphrases all the time, but it's a by-product of what I do. It can be wearing, this general sense of who you are all the time, a low-level rumbling of recognition. But it's worse for Beckham, except he quite likes it. I don't thirst for the film-premiere world."

Whether he likes it or not, though, he is lumbered with it, since his unlikely friend, the Hollywood star Johnny Depp, keeps getting roles for him in his movies. The latest is Neverland, about the playwright J M Barrie. "Depp pulled a few strings to get me a cameo as a stage manager. He's very good. He got me an audition for Sleepy Hollow as well. Very sweet."

Neverland also stars Dustin Hoffman, another huge star who has emerged as a fan of The Fast Show, which is shown to small audiences but considerable acclaim on BBC America. "The biggest help we have in America is old Depp, larging it up all the time on behalf of The Fast Show," says Whitehouse. "I'd heard years ago that he was a fan, when he was with Kate Moss and used to hang about with the Gallaghers and all that. I knew Noel was a fan, but when I first heard about Johnny Depp I was very sniffy. Then I heard about it again from a few sources, and thought, 'He obviously likes it.' Eventually his agent got in touch with mine, and we went out for dinner. I think I underwhelmed him for a couple of hours, but he did his Rowley Birkin impersonations and I could see he genuinely knew his stuff."

In due course, Depp was invited to take part in the third, and final, series of The Fast Show. "We sometimes asked musos to be in sketches and they'd say yes, then when the time came to do it, they'd say, 'Oh, sorry, we're on tour.' I was expecting a similar thing with him, especially when his agent started saying, 'It's very tricky for Johnny, he's got to be here, there.' I didn't believe it until the old car trundled into TV Centre."

Depp featured as an American tourist in a "Suit You, Sir" sketch, assailed by the revolting menswear assistants played by Whitehouse and Mark Williams. Like Harry Enfield – whose relationship with Whitehouse has followed a fascinating and sometimes dyspeptic course in the years since Enfield was the big star and Whitehouse the anonymous writer – I always found the "Suit You, Sir" sketches one of The Fast Show's lesser attractions. But Depp so wanted to be in it that he flew in from Poland, where he was working, and then promptly out again, much to the amazement of an American film producer that Whitehouse subsequently met. "He said [cue a nuance-perfect impersonation of an American film producer], 'Jahnny Depp did a sketch in your TV show, for nothing? We offered him $20m and he turned us down!'"

As wonderfully improbable as it is that Whitehouse should have collaborated with Depp, a greater improbability once loomed; that Whitehouse himself might become a movie star. The last time we met, I remind him, he was being courted by another Fast Show devotee, the American film director John Hughes, the maker of Ferris Bueller's Day Off and Planes, Trains and Automobiles.

He laughs. "He was very keen for us to write for him, but we were brutally frank and said we didn't have any ideas. He wanted us to remake stuff, but we couldn't have done it. Anyway, we didn't quite believe him. He had treated Harry [Enfield] quite shabbily a couple of years before.

"It's a funny story, actually. For about three days, Harry and John Hughes were best mates. John Hughes invited Harry to his ranch in Chicago, where he's built a hill because there wasn't one. Harry said they had a great time. They'd been out fishing in a lake, had a laugh at some film producer's expense, and then it came to day three, the day of Harry's audition. Harry read for the part, but apparently he didn't do it very well, and two days later there'd been no word at all from John Hughes. Then a van rolled up instead of the usual limo, took him to the airport, and he never heard from John again."

Whitehouse roars with laughter. "So when John Hughes is saying, 'Your show, it's so cool, it's got so many levels and layers,' I'm like, 'Oh yeah, we'll see how many layers and levels I've got.' But hats off to him and his company. They kept pursuing us and they were very courteous. I doubt if they even gave it a second thought that they were rude to Harry, and it probably wasn't a personal snub, but even so it's a nice bit of armoury to have when you approach that world. You know what it can be like."

'Happiness' is on BBC 2 tomorrow at 10pm.

Deborah Ross returns next week