Jenni Murray, the presenter of BBC Radio 4's Woman's Hour, has announced she has breast cancer.
The veteran broadcaster told listeners she would not "be around for a while in the New Year" but added that her "prognosis is excellent".
She said she planned to be back "as soon as I feel up to it".
The 56-year-old, who also hosts The Message on Radio 4, will have surgery in the coming weeks, followed by appropriate treatment.
Murray has been the regular host of Woman's Hour since 1987.
Born and educated in Barnsley, Murray joined BBC Radio Bristol in 1973 and was a presenter for BBC TV's South Today between 1978 and 1983.
She moved to Radio 4 in 1985 to become a presenter on the Today programme.
Murray wrote a weekly column for the Daily Express from 1998 to 2000 and is the author of two books - The Woman's Hour: A History of Women Since World War II, and Is It Hot In Here: A Modern Guide to the Menopause.
In 1999 she was given an OBE for services to radio broadcasting.
"Our thoughts are with Jenni, her friends and family at this difficult time," said Christine Fogg, chief executive of Breast Cancer Care.
Murray (left) became a presenter on the Today programme in 1985
"We wish her well with her forthcoming treatment and look forward to her return to Woman's Hour in the New Year."
"Everybody on the programme has been really impressed by the straightforward way in which Jenni has been dealing with this," said Murray's Woman's Hour colleague Martha Kearney.
"She's been incredibly strong and we're all wishing her the very best for a speedy recovery."