The Little Britain comic will take on the roles of host, team captain and panellist alongside a rotating series of special guests in the Red Nose Day challenge.
24 Hour Panel People will be broadcast online and also partly on BBC One and BBC Three. It will pay tribute to popular panel shows such as Just A Minute, Have I Got News For You and Never Mind The Buzzcocks.
Sean Lock, Leigh Francis and Jason Manford will be among the stars helping Walliams out during the challenge.
"This is an amazing challenge. I just hope I don't fall asleep or burst into tears," said the comic.
The whole 24 hour panel marathon will stream live on March 5-6 on the BBC Red Nose Day website.