Johnny Vaughan will replace Chris Tarrant as host of London's Capital FM breakfast show in spring 2004.
Vaughan will take over the show in March 2004
Vaughan has signed a three-year deal to present a programme that attracts audiences of over 1.5 million a day.
"I'm used to early mornings so getting up won't be a problem," he said. Chris Tarrant praised Vaughan as "vibrant, lively, funny and exciting".
Meanwhile Vaughan will host weekly debate show Fighting Talk on BBC Radio Five Live from Saturday.
The announcement of Vaughan's new role comes after months of speculation that Tarrant - who has been at the station for 17 years - was leaving Capital's flagship show.
"This has been an incredibly important decision for us. Chris Tarrant has been with the company for 17 years and he's certainly an impressive act to follow," Capital Radio chief executive David Mansfield said.
"However, I believe that Johnny is simply the best presenter to take over the biggest show on London's leading radio station," he said.
Vaughan, 37, signed a £3m deal with the BBC that ends in May 2004. He hosted a talk show on BBC Three and also starred in a sitcom, 'Orrible, that suffered poor ratings.
Tarrant, meanwhile, will continue to host the ITV1 quiz Who Wants to be a Millionaire?
Vaughan, who will start his new job in March, said he was "thrilled to bits".
"Almost from the day I had to leave The Big Breakfast, I really missed the
buzz of doing something live each day," he said.
"I think when you look at a breakfast DJ they are more in touch with their
audience than anyone else. They have got to go to work and so do the audience and the listeners can feel that."
Tarrant, 56, said of his replacement: "He was very together and very quick on The Big Breakfast and that's exactly
what's required for the breakfast show, as well as being able to get out of
He added that he was surprised the BBC's contract with Vaughan allowed him to work for a commercial rival.
"I didn't think we could get him away from the BBC - I thought they would
have tied him up with one of those bi-media deals," he said.
"They should have done and I suspect that if they had got a whiff of this
they would have done."
Tarrant said he was pleased the "ridiculous" speculation about his future was coming to an end - and explained he was hoping to wind down his broadcasting commitments over the next few years.
But he added: "I have lots of Millionaires to do in 2004 and I'm
committed to Tarrant On TV until 2005, so I have a lot of TV stuff."