Michael Arndt, an Oscar-nominated screenwriter on Toy Story 3, has come aboard Disney’s feature version of Phineas and Ferb, Deadline confirmed Friday. Arndt, who also was among scribes on Rock of Ages and an Oscar winner for Little Miss Sunshine, is doing a polish on the script by the Disney Channel series creators Jeff “Swampy” Marsh and Dan Povenmire. Addition of Arndt to the mix illustrates the importance to Disney of transferring the whimsical stepbrothers’ adventures to the big screen. The plotline for the Phineas and Ferb movie hasn’t been revealed, but the LA Times reported that unlike the TV show it will be a mix of live-action and animation. It’s scheduled to hit theaters July 26, 2013, accompanied by scads of licensed marketing tie-ins.