Paul O'Grady has pulled out of a Comic Relief singing and dancing competition for personal reasons.
The entertainer had been set to appear as a judge on Let's Sing And Dance For Comic Relief.
He has been replaced by comedian Katherine Ryan ahead of Saturday night's first show.
The BBC programme will see a line-up of stars dressing up to re-enact their favourite musical moments and will be hosted by ex-Great British Bake Off presenters Sue Perkins and Mel Giedroyc.
A BBC spokeswoman said: "Comedian Katherine Ryan will step in alongside Frank Skinner and Jo Brand on the guest judging panel tomorrow night for the first live show of Let's Sing And Dance For Comic Relief.
"Paul O'Grady is unable to be on the panel this week and wishes all the contestants the best of luck."
I t is unclear whether O'Grady will return for next week's show.
:: Let's Sing And Dance For Comic Relief is on BBC One on Saturday at 6.45pm.