Veteran DJ Sir Terry Wogan today confirmed he is to quit his BBC Radio 2 breakfast show, with Chris Evans taking over the slot.
Sir Terry, 71, told listeners of the long-running and much-loved 'Wake Up to Wogan' that he would be stepping down at the end of the year.
But he said that he was not quitting the airwaves altogether and had an exciting new show lined up.
He said: "This is the hardest thing I have ever done in my broadcasting career, to say goodbye to you in the mornings."
Making the announcement live on air, Sir Terry said: "Now, if you'll pardon me, I've a little bit of news of my own.
"If the mail is anything to go by, most of the listening population have spotted a report that next year I'm going to turn into Chris Evans.
"And I hate to tell you, but it's true. I was hoping to break it to you, my loyal listener, more gently.
"I wanted to be the first to tell you. It's the least I owe you, for endless years, countless hours of morning companionship, friendship, good humour, and laughter. Your loyalty and support has been a beacon of love in my life."
Sir Terry said the decision was the hardest of his broadcasting career.
He explained: "I'd rather leave while we're in love, as the song says, while the programme is the most popular on British radio, while we still delight in each other's company.
"And so we will, until the end of the year, when my good friend Chris Evans takes over. I know that you'll give him the same love and affection you've always shown to me."
Announcing that his new radio project, he added: "And in the new year, I'll be starting a really exciting new show, live from the BBC Radio Studio at Broadcasting House in front of you, as my live audience, presenting the very pinnacle of live music, artists, guests, and of course, you, your mail, your warmth, your wit.
"So, this is not goodbye, it's not even au revoir... As they used to say when I was a lad 'See you later alligator... in a while, crocodile'."
Sir Terry first joined the Radio 2 Breakfast Show in April 1972 when he was just 34, with his banter and observations of life quickly proving a huge hit with the station's audience. He was soon pulling in around seven million listeners.
However he left the show at the end of 1984 to take up his long-running stint on BBC1's three-times-a-week chat show Wogan which ran from 1985 to 1992.
He rejoined Radio 2 in 1993 and has presented Wake Up To Wogan since then.
Tim Davie, director of audio and music at the BBC said: "Terry is a legendary talent and I'd like to pay tribute, on behalf of the BBC and his millions of devoted listeners, to his unique place in UK broadcasting history.
"I'd like to thank Terry for entertaining his army of fans for many years and I'm delighted that he has agreed to continue to entertain the nation on Radio 2."
His replacement was gracious about the current host today.
Evans said: "This is very much Terry's story, not mine, as well it should be. To step down from something you have done so well and for so long and obviously still enjoy doing must be a tough call even for such a stoic as Sir Tel.
"That said, although I will miss the drive-time show which I have loved for the last three and a bit years, I couldn't be more excited at the prospect of hosting the flagship show on one of the BBC's national networks."
Sir Terry's departure is expected to be greeted with consternation by his army of fans known as TOGs (Terry's Old Geezers or Gals).
One listener writing on the BBC Radio 2 message board said the move was a disaster.
The poster wrote: "What a disaster it will be to lose Wogan in the mornings and worse still to get Chris Evans! who is ok if a little childish at drive time but would be terrible to wake up to in the mornings."
Another wrote bringing in Evans for the breakfast spot was a "mistake".
But other posters were more positive, with one describing Evans as "excellent and just what is required".
Evans's previous appearances on BBC radio breakfast shows ended on bad terms.
In the mid-1990s he hosted the Radio 1 morning slot but, already a controversial figure for his programme's occasional near-the-knuckle content, he went on to have a public fall-out with the station.
His drinking benders would impact on his show, he demanded more holidays from his employers and branded station boss Matthew Bannister "the fat controller".
He was eventually sacked in 1997 but returned to the BBC in 2005 to front a weekend show, and then moved to drive-time the following year.
Writing in his blog last night prior to today's announcement, Evans said: "I just went for a walk in the garden with my son Noah to contemplate what might happen in the next 24 hours and who knows what else in the next few years.
"With the last of the day hanging on to say goodbye, I looked into his seven-month-old big bluey-brown eyes as they sparkled magically.
"He was gazing around in wonder at something he'd never seen before - the magnificence that is the deep green of the trees' leaves surrendering to the first tones of a new season under an already golden sky, his first autumn beginning to take shape. All the perspective I needed."
He added: "Good luck Mr W. I promise I will do my utmost not to let you and your listeners down."
Norman Macintosh, an influential member of the TOGs, said Sir Terry was a national treasure and his presence would be greatly missed on the morning airwaves.
The 55-year-old, from Newport, South Wales, said: "The announcement comes as a bit of a surprise really but his show couldn't go on for ever.
"It's better that he chose to go out on a high rather than be asked to leave, which is what's happened to most people.
"He's probably the best radio presenter going, he's got such an easy style and is just a consummate professional.
"It feels as though he's been around for ever and in that time he has become a national treasure."
Of Sir Terry's replacement Mr Macintosh, who helps run a charity calendar for TOGs, said: "Chris is a totally different person and hopefully we can have the same relationship with him as we did with Sir Terry."
Pink Floyd drummer Nick Mason paid tribute to Sir Terry, describing him as a hugely important broadcaster.
Mason, who was recording a charity single with Sir Terry at London's world-famous Abbey Road studios today, said: "Everyone knows he's been incredibly important for broadcasting.
"It's interesting to see just how newsworthy his announcement is today and even more interesting that he's being replaced by Chris Evans, which seems to have driven everyone into a frenzy."
Former Rolling Stones star Bill Wyman said the broadcaster was a "good Irishman".
He said: "I've known Terry for quite a long time. He's done a bit for charity and I think he's great, he's a good Irishman.
"Everybody has to stop sometime. Your time comes and you move on. We will still see him around, I'm sure."
Sir Terry said he had hoped to announce his departure next week but had been forced to bring it forward due to growing press speculation.
He said: "As always, the great British Press anticipated me and, rather than deny it now but then announce it next week, I decided to confirm that I was leaving the show.
"It's the hardest thing I've had to do in my career."
Playing down his success, he said: "I've just worn them down. If you do something for long enough, as I have, people confuse longevity with merit. They begin to feel sorry for you."
Sir Terry's breakfast rival, Radio 1 DJ Chris Moyles, wished the veteran broadcaster well in his own inimitable way.
"Terry Wogan is a phenomenal broadcaster. It's the end of an era Terry not being on in the morning any more," Moyles said.
"I, like millions of others, will miss hearing his great Irish brogue every morning.
"That said, yay for me! I will be the number one breakfast DJ in Britain!"
Moyles became Radio 1's longest-serving breakfast show presenter today, overtaking the record set by Tony Blackburn more than 30 years ago, and has begun a nationwide tour with his show to celebrate.