The sketch series was a staple part of the iconic kids show SMTV Live in the late '90s and saw the trio parody the sitcom Friends, with different celebrity guests appearing each week.
Last year Deeley reunited with Ant and Dec for a one-off documentary looking back at the success of SMTV and now she has agreed to return again for a one-off Chums special, according to The Sun.
The new skit will play out during Ant & Dec's Saturday Night Takeaway on Saturday, March 20 as part of the 'End of the Show Show' segment.
"This is the reunion SM:TV fans have been calling for. It's going to be epic," a source told the newspaper.
"After the success of the SM:TV special, Ant & Dec, Cat and bosses thought this would be the perfect opportunity.
"Cat was taking part in the show for a brilliant Undercover segment anyway, so they thought they'd give the people what they want.
"Producers are already thinking of brilliant things they can do and plan lots of star cameos. It will feature as the End of the Show Show segment."
The final episode of Chums with the trio saw Dec ditch Cat (The Dog) at the altar on their wedding day. body check tags ::