Adding Some New Zip to '90210'

1. Kathleen Robertson

*Role: Clare Arnold, attention-starved chancellor's kid and Kelly and Donna's future roomie. *Last seen: On Canadian TV, including the series Maniac Mansion (airing in the U.S. on the Family Channel). *On Clare: ''She is definitely going to spice up the beach house. She's going to be a little more sane (than in her several appearances last season), which is very good for me. I won't have to wear lingerie anymore.'' Or handcuffs? ''Wellll....''

2. Jamie Walters

*Role: Handyman and fledgling rocker Ray Pruit, who sounds a little like John Mellencamp but looks like Corey Hart. *Last seen: Engaged briefly last year to Drew Barrymore; playing a fledgling Mellencamp-style rocker on the 1992 Fox bomb The Heights(which yielded a No. 1 single, ''How Do You Talk to an Angel''). His first solo album, Jamie Walters this month. *On Ray: ''He's an outsider, and he's got a mean streak. And I get to play my music. So it's ideal. And it takes me 15 minutes to get to work.''

3. Tiffani-Amber Thiessen

*Role: Valerie Malone, trouble-making daughter of Walsh family friends, who moves into Brenda's room. *Last seen: As the much more demure Kelly on NBC's Saved by the Bell. *On Valerie: ''Her father commited suicide, and she's going through a rough stage. I start off with Steve, then I get involved with Dylan. But I don't sleep with both of them.''

4. Mark D. Espinoza

*Role: Jesse Vasquez, law-student husband of Andrea and father of their child; also the show's first regular character of color. *Last seen: On Broadway, on Chicago theater stages, and, since last fall, as a part- time 90210er.*On Joining The Cast: ''I don't have the label '90210' that the other guys have, which can be good and may also hold them back. But then again, I might be living in a trailer home a year from now.''