DERMOT O'Leary took a cheeky swipe at Ant McPartlin and Dec Donnelly on This Morning.
The presenter suggested the pair had "hidden secrets" as he quizzed them on the ITV daytime show.
Ant and Dec were appearing via video link from Florida where they're filming Saturday Night Takeaway.
They told Dermot and his co-host Alison Hammond that Stephen Mulhern would be making an appearance on Saturday to play 'In for a Cent'.
Dermot asked: "What does he have on you to keep coming back?
"He knows where the bodies are buried."
Ant and Dec laughed off the question as they continued to fill in fans about what to expect from the special show.
The pair celebrated Stephen's birthday as he turned 46.
He wrote on Twitter: "Thanks so much for your birthday messages everyone!
"I’m running around a theme park and wearing my gold jacket to celebrate! Sending lots of love x."
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Dozens of his followers wished him a happy birthday, with Davina McCall writing: "Happy birthday sweet cheeks!"
Another teased the youthful star: "I love this. Happy Birthday. Your 21 again! I hope you are having the best day EVER. Enjoy Florida. Xxxx."
The TV star is Stateside at Universal Studios in Orlando filming Saturday Night Takeaway's epic finale.
And another huge TV project was recently confirmed for the In For A Penny host.
ITV has revived Deal or No Deal after nearly a decade off air - and Stephen has replaced Noel Edmonds as its presenter.
Speaking about taking over the reins of the show, Stephen said last week: "Wow what an opportunity, I’m beyond excited to be hosting the brand-new series.
"I’ve always been such a huge fan of the show, so much so, I’ve been practising at home with small cereal boxes! It looks so simple but it's an incredibly compelling game for both those playing and the viewers watching at home.
"It’s one of the greatest shows of all time and to be the new host is an honour! I can’t wait to get started."