JOURNALIST LISA LING GUEST STARS IN A NEW EPISODE OF "PHINEAS AND FERB," FRIDAY, MAY 13 ON DISNEY CHANNEL

Ask a Foolish Question" - When Candace discovers that Phineas and Ferb have invented a computer that can answer anything, she asks it how she can finally bust her brothers once and for all. Meanwhile, Dr. Doofenshmirtz loses the key to his latest invention, the "Take Over the Tri-State Area-inator," and Agent P must find it before he does.

"Misperceived Monotreme" - Perry misses his 100th battle against Dr. Doofenshmirtz when Candace takes him to the Charity Pet Wash with her. Perry's absence goes unnoticed when a typical platypus at the Danville Zoo stops Dr. Doofenshmirtz's plan to zap his brother with his "Least Likely-inator." Meanwhile, the boys build a fun house Phineas and Ferb style.

This episode of "Phineas and Ferb" airs FRIDAY, MAY 13 (9:00-9:30 p.m., ET/PT) on Disney Channel.

"Phineas and Ferb" stars Vincent Martella as Phineas Flynn, Thomas Sangster as Ferb Fletcher, Ashley Tisdale as Candace Flynn, Mitchel Musso as Jeremy, Caroline Rhea as mom Linda Flynn-Fletcher, Richard O'Brien as dad Lawrence Fletcher, Dee Bradley Baker as Perry the Platypus, Alyson Stoner as Isabella, Jeff "Swampy" Marsh as Major Monogram and Dan Povenmire as the nefarious Dr. Doofenshmirtz. "Phineas and Ferb" is a production of Walt Disney Television Animation.

Journalist Lisa Ling ("Our America with Lisa Ling") guest stars as the zookeeper.

"Ask A Foolish Question" and "Misperceived Monotreme" were written Martin Olson and directed by Jay Lender.

"Phineas and Ferb" carries a TV-G parental guideline.