Phineas and Ferb: Across the 2nd Dimension Phineas and Ferb: Across the 2nd Dimension

Phineas and Ferb are about to embark on an adventure where they learn their pet platypus Perry is a secret agent in the TV movie Phineas and Ferb: Across the 2nd Dimension (Friday, 8/7c, Disney Channel).

Based on the Emmy-winning series Phineas and Ferb, the film takes the stepbrothers into a kind of parallel universe that eerily resembles their home. Once there, they come face to face with their alter egos and find out Perry (voiced by Dee Bradley Baker) is known as Agent P. The three band together, along with sister Candace (voiced by Ashley Tisdale), to stop the evil Dr. Doofenshmirtz, who plans to follow the gang back to their real home in his quest for world domination.

Series creators Dan Povenmire and Jeff "Swampy" Marsh say the film allowed them to develop the characters much further. The Disney show has featured numerous guest voices, including Tina Fey, Ben Stiller and Michael Douglas, and the duo say they're always surprised, but thrilled, to hear that it's not just little kids who watch the show.

"We had Tom Bergeron on the show and he said, 'I'm on this big network show and my daughter doesn't care at all, but because I'm here, I am now her hero ... She's 20, she's in college.'" Povenmire says.

Adds Marsh: "We always knew there was stuff there for the older folks ... so when you hear people say thanks for making something we can watch with our kids or as a family, I'm glad people out there discovered it."

Watch our interview with Povenmire and Marsh: