Marianne Moore, played by Leslie Bega (of "Head of the Class" fame), is a character seen on Beverly Hills, 90210, the first series of the Beverly Hills, 90210 continuity.  She appeared in the pilot episode, Class of Beverly Hills.

Marianne Moore was a popular West Beverly Hills High School student who gave a party at her lush Beverly Hills home while her parents were away during the pilot episode. At this party, she meets Brandon Walsh, the new kid in town who didn't know anybody.

They went out on a date and spent a good time in Marianne's hot tub, but Brandon stopped it before it went any further.

Marianne was fairly withdrawn, tired of the gossip of high school and the lifestyle her parents have encouraged her to live. She found Brandon a refreshing change from the superficial guys she usually dated until the next day, rumors began circulating that Brandon and Marianne slept together. Worse yet was the fact that Brandon didn't exactly discourage the rumors.

As a result, Marianne is angry because she let herself be vulnerable to a guy who turned out to be no different than the rest. However, Brandon eventually confessed over the school radio station that he and Marianne never slept together. They share a polite reunion before Marianne decided to do something crazy, like staying home on a weekend.