From www.wdwinfo.com

Star Wars episode of Phineas and Ferb to air next year
Jul 20, 2013

Phineas and Ferb will join forces with Star Wars next year in a TV special, something the creators (Dan Povenmire and Jeff "Swampy" Marsh) have been planning ever since they heard that Disney had purchased Lucasfilm last year. Povenmire said, "When I saw that news break, I drew a picture of Doofenshmirtz as Darth Vader and texted it to the head of Disney TV animation and wrote, 'I smell crossover!'"

According to TVGuide.com, Phineas and Ferb will spend the summer living next door to Luke Skywalker on Tatooine and find the plans for blowing up the Death Star. Of course, problems ensue as "Darth Enshmirtz" creates a "Sith-inator" to blow up the Rebellion, Agent P finds himself stuck in carbonite, and Ferb becomes an evil Sith.

Production has already begun on the Star Wars episode. Next month, the first crossover show with another of Disney's newest acquisitions, Phineas and Ferb: Mission Marvel, will premiere.