1. Maggie & Jake Gyllenhaal
This acting duo got their start when they were both cast in the psychological thriller Donnie Darko, playing the role of—what else? Siblings.
2. Shirley MacLaine & Warren Beatty
From the time they were teens, Shirley and Warren were destined for stardom. Both are Oscar®-winning actors—Shirley best known for her iconic roles in Terms of Endearment and The Apartment, and Warren with film achievements including Bonnie and Clyde and Reds.
3. William, Stephen, Alec & Daniel Baldwin
With a long list of TV and film roles, the Baldwin brothers seem to be everywhere—including the tabloids. Although all four brothers are actors, they didn't grow up in Hollywood. Their mother, Carol, founded the Breast Care Center and their father, Alexander Ray, was a teacher.
4. The Wayans Brothers
Acting runs in the Wayans family—brothers Marlon, Shawn, Damon and Keenen Ivory are actors, directors and screenwriters who often appear in each other's films, like Scary Movie, White Chicks and Little Man.
A new generation of Wayans is also breaking onto the scene—some of the brothers' children have begun acting!
5. David, Alexis, Patricia, Richmond & Rosanna Arquette
From David's role in the campy thriller Scream to Alexis' memorable voice in The Wedding Singer, the Arquette siblings have acted in all types of films. Show business runs in the family—their father, Lewis Arquette, was regularly seen on series like The Waltons and their grandfather, Cliff Arquette, was famous for his comedic alter-ego "Charley Weaver," a regular on the game show Hollywood Squares!
6. Emilio Estevez & Charlie Sheen
Emilio goes by the family's surname, while brother Charlie opted to adopt his father's stage name, Sheen. Emilio is immortalized as a member of the infamous 1980s “Brat Pack” while Charlie currently stars in the uber-successful sitcom, Two and a Half Men, making Estevez and Sheen stars in their own right.
A passion for acting must run in the family. Their father Martin Sheen has been a Hollywood fixture since landing his first film role in the 1960s.
7. Andrew, Luke & Owen Wilson
Considered part of the "Frat Pack," the Wilson brothers have starred in their share of comedies. Luke has taken on movies like Old School and Legally Blonde, and Owen starred in Wedding Crashers and Marley and Me. The brothers combined forces for The Royal Tenenbaums, which also featured their older brother, Andrew Wilson.
Photo: George Burns/Harpo Studios
8. Mary-Kate & Ashley Olsen
The Olsen twins' popularity began when Mary-Kate and Ashley
were just 9 months old, appearing as baby Michelle on the television show Full House
. At just 7 years old, the mini-moguls co-founded Dualstar to market their images to tweens around the world—from DVDs to cosmetics to furniture. At 18, the girls took over the company, estimated to be worth millions.
The twins are now focusing on their passion for fashion—in 2006, they launched a high-end clothing line called The Row, followed by a more contemporary line, Elizabeth and James.
Watch the Olsen twins, one-on-one.
9. Ben & Casey Affleck
Ben established himself as one of Hollywood's leading men in films like Armageddon and Pearl Harbor. Casey was right behind, landing supporting roles alongside Ben in Good Will Hunting and Chasing Amy. In 2007, Ben co-wrote and directed Gone Baby Gone, starring none other than his baby brother Casey.