Jonas Brothers -- All Four Of Them! -- To Star In 'Walter The Farting Dog'

JoBros will work with Farrelly brothers on film adaptation of book series.

The have lined up another project to add to their already busy schedules. In addition to their 3-D concert movie, a TV show and, you know, that whole music career, the guys have just signed on to star in the film "Walter the Farting Dog," based on the books of the same name, Variety reports.

And they're adding another familiar face to the mix — their younger brother Frankie, known as Bonus Jonas. The guys, who previously starred in "Camp Rock," will play musicians asked to watch the flatulent, overweight dog by a dying aunt.

"By the time they've driven the dog home, everybody's head is out the window of the family station wagon but Frankie, and only because he has a serious sinus problem and doesn't notice the stench coming from Walter," said Peter Farrelly, who will produce and possibly direct the film with his brother Bobby. (Bathroom humor is, of course, nothing new for the duo, whose résumé includes "Dumb & Dumber" and "There's Something About Mary.")

Frankie, along with the dog, gets into some silly situations, like thwarting jewel thieves and saving koi fish. The film is set to start filming next spring.

Recently, the JoBros released the video for their single "Lovebug," starring their celeb crush Camilla Belle. The guys are also hard at work on their TV series, "J.O.N.A.S.!" in which they'll play a band trying to balance fame and normal teenage life.

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