Professor Stephen Hawking 'asked to make snot jokes' for Red Nose Day
Ed Sheeran, Professor Stephen Hawking and comic duo French and Saunders have signed up to help promote Red Nose Day.
Chart star Sheeran, 25, will be seen singing with children, many orphaned by the recent Ebola outbreak, on the streets of Liberia.
He said: "I'll never forget the kids I met on this trip. When we sang together, they were in such high spirits despite everything they'd been through.
"It was an incredibly eye-opening experience and I'm really proud to support Comic Relief and see what they are doing to help these children have a better future."
Professor Hawking, 75, voices a Red Nose character - Nose-it-All - on a comic strip game, along with Warwick Davies, Hugh Dennis, Nick Grimshaw, Sir Lenny Henry, Harry Hill, Alex Jones, Katie Price and YouTuber Joe Sugg, which is now online.
He joked: "I'm a world-renowned scientist who has shaped our understanding of the universe and I am being asked to make snot jokes. I must really like this charity."
Dawn French and Jennifer Saunders will be among those helping to present the night itself, along with Sir Lenny, Miranda Hart, comedian Romesh Ranganathan and Jonathan Ross.
The night will also feature sketches on BBC1 with TV character Mrs Brown from Mrs Brown's Boys and comedy duo Vic and Bob causing chaos backstage while bringing back classic characters the Stotts.
Chat show host Graham Norton will be seen interviewing guests on a "ludicrously long sofa", while an "international music mega star", yet to be announced, will also take part in proceedings.
Meanwhile, Reggie Yates, Katy Brand, Russell Kane, Hugh Dennis, David Baddiel and Michaela Coel drive across Kenya and Uganda to deliver supplies to Comic Relief funded projects.
Red Nose Day - helping to change lives in the UK and Africa - takes place on March 24.