There's no rivalry when these A-list siblings get together on the red carpet:
Ben and Casey Affleck
These two have no problem sharing the limelight: Casey, 32, stars in his big brother's directorial debut, Gone Baby Gone. The younger Affleck tells Us he doesn't feel overshadowed by his more famous sib. "I don't know anyone who kind of goes around in their life thinking, 'God, how do I get out of this shadow?' I'm kind of the center of my own universe."
Penelope and Monica Cruz
These Spanish knockouts add a double dose of dazzle when they're together. Monica, 30, is frequently her big sister's plus-one at Hollywood events, and the two are so in-sync when it comes to style, they developed a clothing (Mango) and handbag line (for Samantha Thavasso) together. Penelope, 33, has said, "my family is the best thing I have, and I spend a lot of time with them."
Kylie and Dannii Minogue
Her older sister is a style icon, but Dannii Minogue, 36, feels no need to compete. "Kylie was always a girly girl. I'm tomboyish, she's princessy," she has said of her 39-year-old sister's trademark glam.
Ashlee and Jessica Simpson
For the Simpson sisters, fame is a family affair. While they may take turns on center stage, each prides herself on her distinctive personal style, so there's no wardrobe envy. Ashlee, 23, tells Us, "We both wear things so differently, it's kind of cool to wear the same designer, but differently."
Haylie and Hilary Duff
These Hollywood siblings are so close, they still live together! "We talk about everything," Haylie, 22, tells Us of her 20-year-old sister. That includes their wardrobe: The sisters often walk red carpets together in coordinating outfits.
Mary-Kate and Ashley Olsen
Call them the Scissor Sisters! The fashion-forward Olsen twins, 21, produce three different clothing lines together. "We're always going to stay true to ourselves and what we believe is chic and flattering and fashionable," Mary-Kate has said of designing with her sister Ashley.
