Mature enough to cozy up to SpongeBob SquarePants

It’s official: Justin Timberlake is all grown up -- or at least he’s no longer worried about proving it.

Timberlake is host of the 20th annual Nickelodeon Kids’ Choice Awards on Saturday, a first-time gig about as far removed as you can get from his glowering (and well-reviewed) drug-dealer role in the film “Alpha Dog” last year. But in a way, “Alpha Dog” set the stage for Timberlake to emcee the nutty awards show for tykes. He is coming off of a year that nixed any lingering notions that he is merely a youth pop act.

Simply put, if you’re anxious about appearing juvenile, you don’t cozy up to SpongeBob SquarePants on live TV.

“It’s true. I think Justin has now established himself as a superstar who can do anything he wants and an artist who is taken seriously by people,” said Paula Kaplan, senior vice president of talent for Nickelodeon and coexecutive producer of the awards show. “He also has a great spirit and just absolutely enjoys this show and has been a part of it since his early days in ‘N Sync.”

The baby-faced Timberlake does have a summer-camp sensibility (he has twice won the award show’s burping contest and is proud of it), but his presence will pull in some older teens and will certainly not bother the moms who enjoyed Timberlake’s hit “SexyBack” or watched him perform on the Grammys, where he was among nominees for album of the year.

The Kids’ Choice Awards show has some other cross-generational stars on tap. One of the performers, for instance, is Gwen Stefani, who is a 37-year-old new mom but dresses like a drum majorette and has a line of dress-up Gwen dolls on toy-store shelves. Other stars on deck for this year’s show include Will Ferrell, Beyonce, Jessica Alba, Steve Carell, Ice Cube, Queen Latifah, Mike Myers, Hilary Duff, Chris Brown, Jon Heder, Chris Evans, Nelly and Ciara.

The Kids’ Choice Awards program airs Saturday from UCLA’s Pauley Pavilion, starting at 5 p.m. for a live East Coast feed. West Coast viewers will see it on tape delay at 8 p.m. Pacific.