The loose-lipped singer will team up with Geri Halliwell and '80s popstar Marilyn for a celebrity edition of the hit Channel 4 show.
The trio will become armchair critics as they pass judgement on the week’s TV as part of Friday’s (9 October) Stand Up To Cancer fundraiser.
The evening’s entertainment will also see a celebrity version of ‘First Dates’, as well as special editions of ‘Alan Carr: Chatty Man’ and ‘The Last Leg’.
Channel 4's head of live events Ed Havard said: "The success of the partnership between Channel 4 and Cancer Research UK on Stand Up to Cancer has been remarkable, and we have raised many millions of pounds to fund groundbreaking cancer trials.
"We are hugely grateful to all the talent and production companies involved in this campaign, and of course to the public who have donated so generously."
‘Stand Up To Cancer’ airs on Friday from 8pm on Channel 4.