Fox's animated series King of the Hill is reeling in the guest voices for episodes set to air during the May sweeps period.

When Hank finds out that only charcoal grillers can enter the Texas State Grill-Off, he partners with Luanne and Luanne’s friend Jason to organize a grilling protest. Unfortunately, their plan backfires on the “Girl You’ll Be A Giant Soon” episode airing Sunday, April 25. Lord of the Rings star Elijah Wood voices Jason.

American Idol Kelly Clarkson guest stars on the following week's episode, "Stressed For Success" airing Sunday, May 2, singing of course. And Johnny Depp lends his voice as Yogi Victor, a yoga instructor who helps Hank become a little more flexible after he throws out his back on the May 9 "Hank's Back" episode.

They join a long list of voice contributors on this season's King of the Hill, including Christina Applegate, Ben Stiller and Brad Paisley.