Jennie Garth has discovered her inner clown. The onetime teen trauma queen of "Beverly Hills, 90210" is just a chucklehead at heart.

And she's about to prove it with "What I Like About You," a bubbly new fall season WB sitcom in which Garth displays her charming gifts for acting goofy. She's funny. She's really funny. Who knew?

"I always knew that I was a kook," says Garth. "So it didn't surprise me."

OK. But after all those years of riding the soap opera roller coaster of heartache, anguish and adolescent angst on "90210," it may come as a pleasant surprise to many TV viewers that the former Kelly Taylor can shake up some smiles with her previously unseen comic skills.

"I loved '90210.' I was such a loyal participant of that show," says Illinois native Garth. "But just to get the opportunity to do comedy was a huge goal of mine. Because having been shot and raped and stalked and all the terrible things that happened to my character week after week, it was just refreshing to go and have fun and laugh at work."

"What I Like About You" pairs Garth with budding slapstick princess Amanda Bynes, who first gained acclaim and favorable comparisons to Lucille Ball as the young star of Nickelodeon's "All That" and "The Amanda Show."

The 16-year-old Bynes plays the rambunctious younger sibling to Garth's more straitlaced, career-focused older sister. Through cockeyed sitcom circumstance, they wind up living together. And that sometimes strained family relationship is where the laughs are located.

Garth has even been blessed with the pratfall gene. She amusingly stumbles over living room furniture on the "What I Like About You" premiere.

"I'm clumsy by nature, so it just worked in my favor. Falling over things just comes naturally to me," she says. "I wasn't sure how the physical comedy was going to go for me. But I just had to go for it. . . . The flip over the couch, I didn't even get hurt."

Only one problem. Since filming the "What I Like About You" pilot episode last winter, 30-year-old Garth has become pregnant.

She and her husband, Peter Facinelli, who stars on Fox's new fall season action drama "Fastlane," are expecting their second daughter in December. Their first child, Luca Bella, is 5.

But because Garth's character on "What I Like About You" is single and has no plans to be pregnant anytime soon, the show's producers are doing some creative filming and using stunt doubles for the more arduous moments of physical comedy.

"I just walk behind things. I carry a lot of stuff," jokes Garth of how the producers are obscuring her real-life expectant-mother physique. Not that Garth is unfamiliar with the drill.

She was pregnant with Luca during the 1996-1997 season of "90210."

"Yeah, we did a lot of 'hiding of Bob,' as we called her at that time," quips Garth. "I remember the final episode that we did of that season, I was 6 months pregnant. They had me shopping at a huge, expensive mall. And I just carried bags in front of me the whole episode."

After the baby arrives in December, Garth says, she'll get back into the swing of slapstick things. But in the meantime, her bright sense of humor isn't being obscured.

A longtime vegetarian, Garth has her own playful take on healthy chow and the need for a little protein.

"It's very hard for me to eat anything with a face," she says. Even seafood faces? "Shrimp is about it for me. They're not very cute."