Wogan, Britain's most-listened-to broadcaster, announced the news to 'Wake Up To Wogan' listeners this morning. He has been working for BBC Radio 2 for 27 years and will continue next year with a weekend show.
Wogan said: "This is the hardest thing I have ever done in my broadcasting career, to say goodbye to you in the mornings. But if not this year, when? Five years? 10? 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."
Rumours had been rife about the move, and Wogan, who is 71, said he regretted he hadn't been able to break the news more gently. He said: "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."
It is the third long-running BBC gig that Wogan has quit, after standing down as the Eurovision Song Contest commentator in 2008 having expressed his disgust with the biased voting. He also gave up presenting 'Points of View' on BBC One, handing over to Jeremy Vine.
Wogan said this morning that he would continue with two other BBC obligations, 'Children In Need' and 'Proms In The Park', until "hell freezes over".
Wogan first presented BBC Radio 2's breakfast show in April 1972, and held the role until 1984. He was back again in January 1993, and has since turned 'Wake Up To Wogan' in to the most-listened-to breakfast show.
Wogan first landed a job at the BBC by sending in a tape to the Head of Gramophone Programmes. Limerick-born Wogan was given a knighthood in 2005.