Penelope Cruz and her sister Monica
Khloe, Kourtney and Kim Kardashian
Kardashian's other siblings: Robert Kardashian, and 1/2 sisters Kendall and Kylie Jenner.
Mary-Kate and Ashley Olsen
Miley Cyrus and her younger half-sister Brandi Cyrus
Ashlee Simpson and her sister Jessica Simpson
Solange Knowles and Beyonce
AnnaLynne McCord and her sister Angel
Donnie Wahlberg and his little brother Mark Wahlberg
Emma Watson and her brother Alex
Ron Howard and his brother Clint
Ashley Judd and her older sister Wynonna Judd
Warren Beatty and his sister Shirley MacLaine
Elizabeth Shue and Andrew Shue
Paris Hilton and her sister Nicky Hilton
Maggie and Jake Gyllenhaal
Dennis Quaid and his older brother Randy Quaid
Luke and Owen Wilson and their less famous brother Andrew Wilson
Rihanna and her little brother Rajad Fenty
Ashlee and Jessica Simpson
Tim Daly and Tyne Daly
Nicole Kidman and her sister Antonia Kidman
Fred Savage and brother Ben
Jessica Alba and her younger brother Joshua
Beau and Jeff Bridges
Nicole and her little sister Sophia Richie
Debbie Allen and Phylicia Rashad
Sienna Miller and her big sister Savannah
Kirsten Dunst and her younger brother, Christian
Jennifer Lopez and younger sister Lynda Lopez
Jennifer Garner, her older sister Melissa and younger sister Susannah
Breanna and Lauren Conrad
Christopher Ciccone, Madonna's younger brother
Victoria Beckham and Louise Adams
Jake and Gwyneth Paltrow
Hayden Panettiere and her younger brother Jansen
Joe, Nick and Kevin = The Jonas Brothers
Linsday Lohan, and her siblings Ali, Cody, and Michael
Dane Cook and a half brother Darryl McCauley
Shawn, Marlon, Kim, Damon and Keenen Ivory Wayans
Julia Roberts and older brother Eric
Angelina Jolie and brother James Haven
Brothers Nick and Aaron Carter
Kevin and Matt Dillon
Jack and Kelly Osbourne
Brothers Ralph and Joseph Fiennes
John Belushi and his brother Jim
The Jackson family
Malia and Sasha Obama
Peyton and Eli Manning
Chad and Rob Lowe
Benjamin Bratt and brother Peter Bratt
Sharon and Kelly Stone
Andrew, Joey and Matthew Lawrence
Brooke and Nick Hogan
Tamera and Tia Mowry
Zac, Isaac and Taylor = the Hanson Brothers
Drew and brother Nick Lachey
The Arquettes: Alexis, Rosanna, Richmond, Patricia and David
Ann, John, and Joan Cusack
Casey and Ben Affleck
Princes Harry and William
The Baldwin brothers: Alec, Stephen, William and Daniel
Haylie and Hilary Duff
Barbara and Jenna Bush
Donny Osmond and his sister Marie
Venus and Serena Williams
Eddie Van Halen with his brother Alex
Jamie Lynn Spears and her sister Britney
Britney Spears and her older brother Bryan
Joaquin Phoenix and older sister Rain
Sean Penn, his mother Eileen, and his brothers Chris and Michael
Dakota Fanning and her little sister Elle Fanning
Virginia Madsen and younger brother Michael Madsen
Charlie Sheen with dad Martin Sheen and brother Emilio Estevez
Candace Cameron, now Cameron-Bure, and older brother Kirk Cameron
Jason Bateman and his older sister Justine
Barry, Robin and Maurice Gibb as the Bee Gees
Jane Fonda and brother Peter Fonda
Mariel Hemingway and her older sister Margaux
Maggie, Lisa and Bart Simpson
The Three Stooges (originally) were Moe Howard, center, his brother Curly Howard, right, and friend, Larry Fine
The Marx Brothers: Chico, Zeppo, Groucho and Harpo
Sisters Eva and Zsa Zsa Gabor
Source: nbcnewyork