Lady Gaga and Natali Germanotta
The popstar and her sister give the cameras their best "Poker Face" on the red carpet.
Emma and Alex Watson
We were already bewitched by the Harry Potter star, but we didn't realize her brother was a model too!
Rachel and Daniel McAdams
She might be The Time Traveler's Wife, but she's this hottie's older sister! Being the coolest big sis ever, the actress brought her brother along to attend the Toronto Film Festival.
Karlie and Kimberly Kloss
The supermodel brings her younger, equally gorgeous sister to the Paper Towns premiere in New York City.
Bella and Kaili Thorne
The Shake It Up star and her actress sister prove that it's all in the genes - or in this case, jeans.
Rosie and Toby Huntington-Whiteley
This Victoria's Secret Angel isn't the only one in her family with sizzling looks! Turns out, her younger brother is a model too!
Justin and Sebastian Theroux
The Zoolander actor (who reprised his role as "Evil DJ" on the runway in the film's sequel) knows a thing or two about fashion. Whether or not his younger brother is a model, he sure looks like one!
Olivia Wilde and Charlie Cockburn
Former House star and her equally gorgeous younger brother walk the actress's rescue pooch in NYC.
Rihanna and Rajad Fenty
"Where Have You Been" is what we're wondering too! The Barbadian beauty and her handsome little brother spend quality time together in NYC.
Kate and Oliver Hudson
The Almost Famous star hangs out courtside with her big bro. While the actress is known for her work on the silver screen, you can catch her brother on Scream Queens.
Gisele and Patricia Bündchen
Double trouble! The supermodel's fraternal twin sister is also super stunning.
Sofia and Sandra Vergara
The Modern Family star poses with her adopted sister. Still see a resemblance? She also happens to be her cousin!
AnnaLynne and Angel McCord
The 90210 actress once tried to get her sisters a guest role on the popular CW series. "I really would love to have my sisters on, because they really are my best friends in the whole world," AnnaLynne told E! News.
Brad and Doug Pitt
Who knew one of E!'s Sexiest Men in Hollywood has a brother who serves as a Goodwill Ambassador?
Jenny, Amy and Joanne McCarthy
Not only does the VH1 talk show host famously have a cousin in Melissa McCarthy, but she also has some beautiful sisters!
Kendra and Erin Andrews
The ESPN reporter hits the red carpet to support her sister's performance in Step Up 3D. What a dynamic duo!
Penelope Cruz and Monica Cruz
No, you're not seeing double - the Vanilla Sky actress' gorgeous younger sister looks just like her!
Taylor and Austin Swift
Good looks run in the family! We can't help but wonder if Austin's got a knack for music like his sis?
Sienna and Savannah Miller
After the stylish sisters parted ways with their Twenty8Twelve clothing collection, Savannah announced her plans to launch an eponymous fashion line.
Nikki and Nathan Reed
The Twilight star's brother flashes a (fang-free) smile while hanging with his famous sis.
Jennifer, Ben and Blaine Lawrence
Three of a kind! The Oscar winner's brothers hit the red carpet to show their support during awards season.
Scarlett and Hunter Johansson
The actress plays a superhero in The Avengers, and it turns out, her twin brother is a super-cutie.
Blake and Eric Lively
We loved her in The Sisterhood of the Travelling Pants, but we'd like to see more of her brother too!