SARA RUE & Joan Rue
Her dad, Marc Schlackman, was a Broadway stage manager, and mom, Joan, a New York actress. Yet both were thrown when Sara, just 8, chatted up an agent at a cast party. "As we left, Sara was saying, 'I'll be calling.' And I thought, 'Oh, mama mia!' " recalls Joan. In a year Sara had a small film role (in Rocket Gibraltar). Now, at 26, she's starring in ABC's Less Than Perfect and an indie flick, Gypsy 83. Joan was far from a stage mom. "If anything, she discouraged me," says Sara. "She was always saying, 'Wouldn't you rather go to the prom?' No way! I want to be an actress!" But Joan, 55, was there as an adviser. "She taught me that sometimes the best thing to do is make a joke and go on," says Sara. "We have the same sense of humor."

SIMON COWELL & Julie Cowell

On American Idol the acerbic judge gets to level the final critique. But that doesn't mean he gets the last word. "Sometimes I do think he's a bit harsh, and I'll ring him up and tell him," says Simon's mum, Julie, a retired ballet dancer living in Brighton, England. The unflappable star's response? "It still kind of stings when you get that call," admits Simon, 44.

Julie, 77, never did let the second-youngest of the five boys she raised in suburban London get away with much. When he'd fake fever by warming his forehead with a teacup, it fooled his dad (Eric, a real estate developer who died in 1999) but not his mum. "I'd say, 'You're going to school!' " she recalls. Simon, who divides his time between L.A. and London, sees Julie biweekly for lunch when he's in England and takes her, his brothers and their families on annual vacations. "He does take care of me," says Julie. "It's hilarious when he and his brothers come—they still pull each other's legs." And hers. "She's not really my mother," Simon says. "I got her from Central Casting—you can go now, Dorothy."

CHERYL HINES & Rosemary Harbolt
Instead of finding fame on HBO's Curb Your Enthusiasm, Hines might still be screaming for visitors to Universal Studios in Orlando. (A park performer, she reenacted Janet Leigh's Psycho shower scene several times daily.) "In '92 I'd decided to move to L.A.," says Hines, 38. Then her stepfather died and "I couldn't leave my mom. But six months later, she said, 'You need to go, I'll be fine.' " Harbolt, an administrative assistant who raised four kids, knew performing was Cheryl's passion. "She liked to do comedy sketches with her sister. She also liked to sing, but I'm glad she didn't pursue that. It's not her strong point." In 2000, after getting her first Curb paychecks, Hines treated Mom to a Mother's Day trip west and her first manicure. This time she thinks Harbolt, 62, deserves more. "In the last year she's had four grandchildren born," says Hines, whose daughter Catherine arrived in March. "She's been going house to house, taking care of babies. If anyone deserves Mother of the Year, it's her."

CEDRIC THE ENTERTAINER & Rosette Kyles
Before he was The Entertainer, the star of Barbershop and beer commercials was the entertainer to an audience of one. "If there was an opportunity to make my mom happy, that would be very gratifying," says Cedric, 40, who with younger sister Sharita was brought up in St. Louis by Rosetta, a reading specialist who's retired. Separated in 1968, Rosetta, now 60, handled single-mom duties while earning a master's degree and insisted Cedric finish college. When he landed a job at an insurance company, "I was thrilled," says Rosetta, who lives in a suburban St. Louis home that Cedric had built for her. "But it didn't fit his personality." What did was moonlighting as a comic. "I went to a performance and thought, 'You know, he is really funny. I think he can do this.' " Cedric still seeks Mom's approval. "If I could make her laugh," he says, "I'm, 'Okay, I'm putting that onstage.' She will definitely tell you the truth."

AMANDA BYNES & Lynn Bynes
"When she was 3, she would put on my clothing and he silly, trying to get attention from her sister and brother," recalls Lynn, 56. But with husband Rick, a dentist whose office she manages, Lynn saw more in their youngest kid than just look-at-me antics. When Amanda was 10, Lynn drove her each day to a summer comedy camp in L.A., one hour from their Ventura County, Calif., home. "She would wake up at 5:30 so we'd miss the traffic," says Amanda, 18, star of Nickelodeon's The Amanda Bynes Show and The WB's What I Like About You. Now Amanda's paying Mom back: She buys clothes for Lynn, who hates shopping, and she spends downtime with Mom crafting jewelry with vintage beads. Says Lynn: "We talk. It's nice time together."