Ten years on from her original sketch, the comic will pay tribute to last summer’s film sequel with her own take, Mamma Mia! Here We Go Yet Again!.
Speaking about returning to play Donna, who was portrayed by Meryl Streep in both films, Jennifer said: “If I could have lived on the fake Mamma Mia set for the last year, I would have been very happy. So I am very, very, very happy to be back.
“This is undoubtedly one of the silliest things I’ve done. But my god I enjoy it so much.”
This year’s Comic Relief will also see the reunion of the Four Weddings And A Funeral cast, who have filmed a special sequel 25 years on from the film’s original release.
Other fundraising activities include Tess Daly and Claudia Winkleman’s 24-hour danceathon and a host of celebrities climbing Mount Kilimanjaro.
However, the annual telethon has been somewhat overshadowed by the Stacey Dooley “white saviourism” row.
The documentary maker come under fire from MP David Lammy, who said she had perpetuated “tired and unhelpful stereotypes” after travelling to Africa to make an appeal film for the charity.