Phineas And Ferb co-creator Jeff 'Swampy' Marsh reckons Dame Judi Dench would make the perfect addition to the cast.
The hit Disney XD show is known for its celeb cameos, with stars including David Beckham, Jonathan Ross and most recently Simon Pegg lining up to lend their voices to the cartoon.
Swampy said: "Judi Dench would be fun. I have no idea who she would play. I think she should work for the OWCA though, the Organisation Without A Cool Acronym. She could be in the British version of that. I think she's pretty cool.
"Or Helen Mirren would be cool too. And Rowan Atkinson! What a great voice. I've got a huge long list - most of the ones on my list are British."
He added: "I almost accosted Ewan McGregor in a restaurant the other night. I thought he'd be pretty good."
Swampy revealed Star Trek actor Simon's cameo on the show was "just great".
"He's naturally very quick with his dialogue and what we do is pretty fast-paced, and so his stuff was just right-on, really quick, a lot of fun."