JONATHAN BRANDIS STARES CONTENTEDLY at the blue and yellow shapes in front of him. “I grew up on this game,” says the 20-year-old actor, happily guiding his Ms. Pac-Man across the video screen. Yet while he may be having a blast, Tatyana Ali, the 17-year-old beauty sitting across from him in the Santa Monica restaurant, is pouting. Brandis notices and makes the ultimate sacrifice: He lets a ghost catch up. “How many guys,” he asks with some pride, “would be willing to kill their Ms. Pac-Man to let their girlfriend play?”

Ah, the things we do for love. Brandis, best known as computer whiz Lucas Wolenczak on the canceled NBC drama seaQuest DSV, and Ali, who charmed viewers as sweet-natured Ashley Banks on The Fresh Prince of Bel-Air until it ended a six-season run on NBC in May, have been dating since May 1995. Usually they shun the teen party scene and cuddle in front of a rented horror flick in the three-bedroom San Fernando Valley, Calif., town-house Brandis, an only child, shares with his parents, Mary, a former teacher, now his manager, and Gary, a former fireman. Or they surf the Internet at Ali’s four-bedroom home, 15 minutes away, where she lives with her parents, Sheriff, a retired New York City police detective, and Sonia, a nurse, and two younger sisters, Anastasia, 13, and Kimberly, 10. Both sets of parents—who have occasionally gone out together—approve of the relationship. “Jonathan is sweet,” says Sonia. “Kind of shy, yet sincere.” Brandis’s mother returns the compliment. “We love Tatyana,” she says. “She’s a real sweetheart. They’re adorable together.”

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When the couple ventures out, they sometimes have problems. “We go to a club, and nine times out of 10 there’s a guy there hitting on her,” says Brandis. “She’s good at getting rid of them, though.” And not just guys. Last year an attractive extra on seaQuest asked Brandis out. When he declined, she showed up at his door—only to be met by an angry Ali. “I said, ‘If a guy tells you to go away, it kind of means you shouldn’t come back,’ ” she recalls. The woman took the hint.

The Ali-Brandis relationship started slowly. At a mutual friend’s Halloween party in 1993, Brandis introduced himself to Ali—but soon left for Orlando, where seaQuest was filming. They occasionally ran into each other when he was at home, and last summer he dropped by her house a few times. She was interested, but kept her distance because, she says, “he was older, probably a lot more experienced. It was uncomfortable.” Finally he told her, “I’m going to stop coming over. And you’re going to miss me.” Looking back, Ali giggles: “I was like, ‘Right.’ ” She pauses and gazes at Brandis, who smiles.. “He was right,” she says, lightly touching his arm. “I called him the next morning.”

Unfortunately he soon had to head back to Orlando. Though her show was shot in L.A., they often visited each other on weekends. “They really worked on keeping their relationship going,” says Don Franklin, who played Cmdr. Jonathan Ford on seaQuest. But not everyone thinks they’re such a cute couple. “We get looks sometimes,” says Brandis, referring to people who frown on interracial romance. One recent evening they were out for a romantic dinner when an African-American man walked up and leaned toward Ali. “I want you to know,” he said, “I watch your show all the time. But now that I see you letting this white man date you, I will never watch your show again.” Though Ali admits “it hurt me that someone could disrespect what I thought was so special,” she insists such reactions don’t “do anything but make us closer.”

To judge from their similar backgrounds, they are pretty close already. Born in Danbury, Conn., Brandis was discovered by a local photographer when he was 2 and got his first gig in an ad for Buster Brown clothing. He soon moved to TV commercials and—after the family moved to California in 1991 to accommodate his career—the occasional movie. In 1993, the year he graduated from the Valley Professional School, he was cast on seaQuest.

Long Island-born Ali began acting at age 4, when her parents brought her to a talent agent, who got her a four-year stint on Sesame Street. She went on to appear with James Earl Jones in Fences on Broadway and to win two Star Search singing competitions. After she landed the role on Fresh Prince at age 11, her family also moved West.

Now a junior at a girls’ private high school in L.A., Ali has made a demo singing tape and hopes for a pop music career. She also wants to attend college. Brandis, by contrast, has no college plans and is looking for a new series role. But though their paths may be diverging, they don’t believe that will strain their relationship. “I love her tremendously,” says Brandis. He averts his eyes, but when he shyly looks at her again, Ali is smiling broadly.