Dec is set to send a 'special message' to Ant in the Saturday Night Takeaway final.
Dec will be fronting the show alone this Saturday night after his debut solo hosting gig last weekend.
The series finale will be airing live from Florida and a special music segment will see Dec apparently sending a message to his pal.
As part of the last show this year, Dec and his co-stars will join in a Singalong to The Rembrandts hit I'll Be There for You, best known as the theme tune to Friends.
A source told the Daily Star: "If ever there were a song to sum up Ant and Dec’s friendship for the past 25 years then the Rembrandts track is it.
“The pair are fans of the comedy show and they even spoofed it on their 1990s SMTV show and called it Chums.”
The news comes as Ant's planned court date for this week is adjourned.
The telly host has stepped down from work commitments and checked into rehab after being charged with alleged drink-driving last month.
Ant was due in court this week but his hearing has now been set back to April 16.
"An adjournment in this case has been agreed, therefore Ant McPartlin will not be appearing at Wimbledon Magistrates’ Court, on Wednesday 4th April 2018," a spokesperson for the court confirmed.
Meanwhile, further details about the Takeaway finale in Orlando have been revealed.
Dec will host the show live from Florida, alongside regular sidekicks Scarlett Moffat and Stephen Mulhern.
According to The Sun newspaper, Hollywood actress Denise Richards and British singer Craig David will join the pair.
Elsewhere in this Saturday's episode, one nation will be crowned the winner in the final of 'Sofawatch'.
Stephen takes his pop-up gameshow stateside in a very special edition of 'In For a Penny', and Scarlett will be on hand to make sure that the ‘Place on the Plane’ winners have an experience they'll never forget.
Finally, The identity of The Overlord will finally be revealed in the thrilling conclusion of 'Saturday Knight Takeaway’ and on top of all that, another lucky player gets the chance to 'Win the Ads' in the only show on TV that says “don’t just watch the adverts - win ‘em!”