Gay Byrne has told listeners to his RTÉ Lyric FM show that he will "not be with listeners next week" as he is to be hospitalised with suspected cancer.
"I shall not be with our listeners on this day next week. Have to go to hospital this week...They think they may have discovered a bit of cancer in the prostate and they think it may have moved up into my back," said Mr Byrne, who is 82 years old.
"I've had the most wonderful, fantastic, robust, good health all my broadcasting life.
"It's my turn now ... Many, many people much worse off. Thank you for your good wishes," added Mr Byrne.
Gay Byrne is a veteran RTÉ broadcaster, having hosted The Late Late Show from 1962 until 1999.
He currently hosts a two-hour music and chat show, called Sunday with Gay Byrne on RTÉ Lyric FM.
"All Gay's friends and colleagues in RTÉ wish him a speedy recovery and look forward to welcoming him back in the coming weeks," said a spokesperson for RTÉ.