BBC presenters including Radio 2's Tony Blackburn and Radio 4 Woman's Hour host Jenni Murray will do battle as stand-up comedians for Comic Relief.
Six presenters have been working with mentors, including Julian Clary and Sandi Toksvig, ahead of a gig at London's Comedy Store on 22 February.
Their progress will be revealed in a three-part Radio 4 series next month.
The winning act, voted for by listeners, will be announced on Red Nose Day on 18 March.
Radio 1's Dev, Radio 3's Tom Service, 5 live's Tony Lives and 6 Music' s Shun Keaveny will also compete.
Blackburn said he was "petrified" at the prospect of performing his three-minute routine while Murray said she was "terrified".
"I have a reputation for corny gags but on radio it takes 10 seconds then I put a record on - I don't have to rely on getting a reaction," Blackburn added.
Tickets for the show are available from the BBC Audiences website.
Stand Up for Comic Relief will be broadcast on Radio 4 at 1100 GMT on 7 and 8 March, and 1830 GMT on 9 March.