Mary Berry will not be a judge on The Great British Bake Off when it moves from the BBC to Channel 4, but Paul Hollywood has said he will remain.
Berry said she was staying with the BBC out of "loyalty", adding that it had nurtured her and the show.
She said Bake Off had been "a unique and brilliant format from day one" and that she was "just sad for the audience who may not be ready for change".
But Hollywood said he was "delighted" to be staying on the show.
"It's been a huge part of my life in the past few years and I just couldn't turn my back on all that," he said.
BBC media correspondent David Sillito said Hollywood had been offered "some appearances" on Top Gear by the BBC before he signed the Channel 4 deal.
Berry wished the show "every success", and added: "Farewell to soggy bottoms."
Last week Mel Giedroyc and Sue Perkins also announced they were leaving, saying they were not "going with the dough".
Hollywood, who has signed a three-year deal, said: "I want to thank the BBC and Mel and Sue for making my time in the tent great fun and really rewarding."
He also thanked his fellow judge Berry in a later tweet, adding: "She has made the right decision for her."
Berry, Hollywood, Giedroyc and Perkins have appeared on the show since the first series was broadcast on BBC Two in 2010.
Jay Hunt, chief creative officer of Channel 4, said: "Paul really is the star baker - an exceptional talent with a twinkle in his eye."
She added: "His wit, warmth and wisdom are vital ingredients in Bake Off's success. I'm so delighted he's coming to Channel 4."
Charlotte Moore, controller of BBC One, said: "Mary is an extraordinary woman, loved and adored by the British public, and the BBC is her natural home," adding: "I can't wait to cook up more unmissable shows with her in the future."
Love Productions, which makes the series, said they respected Berry's decision but that the whole crew would "miss her".
Former Culture Secretary John Whittingdale told BBC Radio 4's World at One he had been "surprised" at Channel 4's decision to buy Bake Off, adding: "It does raise questions about whether or not it's appropriate."
Whittingdale said the network had a remit to be distinctive and different - but accepted the need to generate revenue through advertising to fund such programming.
"But in this case, they have essentially poached a show, which is very successful, from another public service broadcaster - and at some considerable cost," he said.
Whittingdale said it was "up to the production company to decide which way to go, but they've followed the money".
He added: "It's one of those shows that is very heavily dependent on the character of the presenters.
"If you take those things away, you're not left with much other than, I suppose, a tent and a few ovens."
Channel 4 told Radio 4 it had "always operated a cross-funding model where more commercially successful programming helps subsidise the delivery of our public service remit".
Former BBC and ITV chairman and Channel 4 chief executive Michael Grade said the programme may not work with Berry gone.
"It's a huge gamble in my view," he said. "All hit shows of this kind are essentially a great format obviously, but fantastic chemistry.
"You make the casting choices of the presenters and you hope to goodness they gel. Well, the four of them have gelled to the extent that they've become national celebrities and national treasures, especially Mary Berry."
Jamie Oliver, who appears on Channel 4 and has been mooted as a potential replacement judge, congratulated Hollywood on his move.
He posted on Twitter: "Welcome @PaulHollywood I know you and the team will do an amazing job on bake off big love j."
It was announced last week that The Great British Bake Off was moving from BBC One to Channel 4.
The network has signed a three-year deal with Love Productions, which makes the programme.
Giedroyc and Perkins left the show the day after its move to Channel 4 was announced.
Channel 4 will begin airing the programme in 2017, starting with a celebrity special in aid of Stand Up To Cancer.
The Great British Bake Off began airing on BBC Two in 2010, and quickly became a ratings success for the channel. It grew in popularity each year, leading to its eventual move to BBC One in 2014.
Last year's final, which crowned Nadiya Hussain as winner, was the UK's most watched television programme of the year, with 15.1 million viewers for the final, according to consolidated figures which include catch-up viewing.