BBC television presenter Christine Bleakley will leave The One Show to join ITV and her former co-host Adrian Chiles, ITV has announced.
She has agreed a three-year deal to present a breakfast show with Chiles and prime time entertainment shows.
The announcement came after the BBC said it had withdrawn an offer for Bleakley to stay, saying she had been "unable to make a decision".
Mr Chiles left The One Show in April over changes to the show's format.
At the time he said he was disappointed that the BBC had added BBC Radio 2's Chris Evans to the presenting team on Fridays, replacing Chiles.
Chiles is now fronting ITV's football coverage and is due to begin hosting a revamped breakfast show, in place of GMTV.
Announcing her move on Sunday after three years on The One Show, Bleakley said: "It is with regret that this experience is coming to an end.
"I have been torn between working with Adrian Chiles and remaining at the BBC. I fully understand the BBC had to move more swiftly than I could, and as a result they've managed to help make my mind up for me."
ITV director of television, Peter Fincham, said he was "thrilled" at Bleakley's move.
"It's great that she'll be reunited with Adrian Chiles and their unique and brilliant partnership will be at the heart of our new-look breakfast show from this autumn.
"Christine will also become a familiar face to ITV peak-time audiences. We can't wait to get started."
Earlier, the BBC had said it was putting "the interests of The One Show audience first and the current uncertainty does not allow us to do that".
The BBC said it had been in discussions with Bleakley about her new contract ever since she told the corporation in April she wanted to be part of a relaunched The One Show following Chiles's departure.
"With that in mind we made a full and final offer to her several weeks ago and made it clear we would not be entering into a bidding war with other channels," the BBC said.
"Christine is still unable to make a decision and therefore we have regretfully withdrawn our offer as we have to put the interests of The One Show audience first and the current uncertainty does not allow us to do that," it added.
Bleakley had explained in an unusual move last week that she was trying to decide whether to accept offers from the BBC or ITV, making it clear she could rejoin Chiles if she chose to.
Celebrities do not normally say anything about contract negotiations until a deal is signed.
At the time, she said of her and Chiles: "We have a brilliant relationship on and off screen, although I can't say I'd particularly relish the idea of dealing with him at 5am every morning.
"On the other hand the BBC is incredibly good to me and I'm very close to everyone on The One Show, which I love presenting. The BBC's plans for The One Show are very exciting."
MPs got involved when it was reported that the BBC had offered her a £900,000 contract over two years.
John Whittingdale, chairman of the Culture, Media and Sport Committee, told The Sun: "This is public money. If she feels she can go and earn vast sums in the private sector, then good luck to her."
Bleakley recently signed a new management deal which means she is now represented by the same company as Chiles.