Let's get this straight right away. Cathy Silvers, 20, is nobody's Bilko. She doesn't deny for a minute that it helped to be the daughter of comedian Phil (Sgt. Bilko) Silvers when she went looking for her first professional acting job last year. Back then she was just a college kid at Cal State (North-ridge). But a family friend who happened to be Dudley Moore saw her perform and promptly sent her to his agent. Cathy's next stop was ABC's Happy Days and—bingo!—she was cast as the sexpot Jenny Piccolo. "Listen, I know they paid more attention to me when they heard who I was," admits Cathy. "But if I couldn't have performed well they wouldn't have given me the job."

That's right, says Happy Days director Jerry Paris. "Cathy just bowled me over. In the first place, she could enunciate, and most kids don't know how. Second, she's like her father—she knows how to zing a punch line."

Sure, but you'd think that anybody who'd grown up as one of five daughters of the irrepressible Silvers must have had a lot of yuks around the dinner table. "He was just like any other father, seeing that we did what we were supposed to do," says Cathy. "But when my sisters and I kid around, we have the same sense of humor, kind of sarcastic but not mean. It's something you just pick up."

Actually, the classic Phil Silvers Show ran for four glorious seasons on I CBS (with the help of such writers as Neil Simon) before Cathy was born. She arrived while her father was starring on Broadway in Do Re Mi. Phil and second wife Evelyn Patrick, a TV actress, already had two daughters (Tracey, now 24, and Nancey, 22). Doctors told the parents this time to expect twins. First came Cathy and then, three minutes later, Candy. Phil remembers his shock at seeing "the first kid had a nose like Pinocchio. I started asking the doctor about it and he explained there was nothing wrong, that when they were born Candy kicked her. In a few days Cathy's nose was back to normal. It was just a little swelling."

The Silvers girls (another daughter, Laury, followed two years later) were raised in Beverly Hills. When the twins (who are fraternal) were 5, their parents divorced and Evelyn moved her daughters to Orlando, Fla. "That was the best thing that ever happened to me," Cathy remembers. "It showed me that there were ordinary people who didn't have others waiting on them all the time."

But in 1968 Evelyn returned to California with her brood and, despite the divorce, she and Phil restored a sense of family. "Our father had an apartment nearby," says Cathy. "We always went to dinner—all of us—on Sunday." After being a high school gymnast and star debater, Cathy turned to the stage at Cal State. The next thing she knew she was up for the part of the oft-mentioned but never-seen Jenny Piccolo on Happy Days. "For seven years on the show we'd been talking about this sexy Jenny," Paris recalls. He considered looking for actresses who were blond and busty "because everyone thinks that's what a sexpot should look like." But after auditioning slight, brown-haired Cathy, Paris decided "the show would be better off with someone cute and funny. It would give the character what we call in the business longer legs, make her last longer." Agrees star Henry Winkler: "She is a wonder at timing, and she has such spunk. There's something very vibrant about her. There's a lot of sunshine."

"She did it all on her own," adds Phil proudly. (He also applauded a Happy Days cameo by Candy, who works full-time as a salesclerk in a men's clothing store in Beverly Hills.) "I was never a stage father, but when Cathy asked for advice I told her to learn her lines and say them real loud. I never told her how to say a joke, but watching her, I've said to myself, 'There's my blood.' "

For Cathy, the high point on the set came last year when her father guest-starred in an episode as Jenny's father. "It was hard working with him at first," Cathy admits, "but I got myself together." Says Phil: "I think she was embarrassed at the beginning. But I treated her strictly professionally. What I really wanted to do was kiss and hold her. I had to remind myself that she's a young lady now. I guess there is a time you have to let go."

Cathy, who dropped out of school after one semester when she joined Happy Days, lives in a one-bedroom pad on the fringes of Beverly Hills, not too far from boyfriend Peter Doder, 22, a law and accounting student. "Never marry an actor," her dad advised, although he had no objection to her becoming an actress. "He told me to remember that it's only a job," Cathy adds, "and that life is getting married and having a family."