The presenting duo's exact schedule for today's Big Red Nose Broadcast has not been revealed, although they have already made an appearance on ITV1's Daybreak. Footage of the challenge will be broadcast during the Comic Relief: Funny For Money telethon on Friday.
"This is giving us the opportunity to do some of the things we've always dreamt of doing, I quite fancy myself as a weather girl or selling my wares on a shopping channel!" Declan Donnelly said.
"We may even return to our roots in kids' TV. It's going to be a long day and a rush to fit it all in, but we're determined to do it."
Ant McPartlin commented: "We're really excited to help kick off Red Nose week.
"The day is going to be a mad dash to fit in as many shows as possible but I'm pretty sure we'll make it in time. Make sure you keep a look out for us, we're hoping to turn up in some of the silliest places."
The pair will also be collecting mementoes throughout the day to auction off.
Comic Relief: Funny For Money kicks off on Friday from 7pm on BBC One.