If you were walking down the street and spotted a famous celebrity, you'd probably recognize them instantly.
However, you might have been in the same place as a famous celebrity's sibling and not even batted an eye!
Here are a few celebrities you might not have known had siblings. See if you can identify them!
via: GettyWhose brother do you think this is? Hint: There's a very strong family resemblance.
via: GettyIt's Emma Watson! That's her brother, Alex. She also has a half-brother named Toby and half-sisters named Nina and Lucy (they're twins!).
via: GettyHonestly, I almost blocked the wrong person in this picture at first, so that should give you a major hint about whose sister this is.
via: GettyThis is Monica Cruz. You could easily mistake her for her sister Penelope.
via: InstagramHere's a ruggedly handsome guy who also happens to be the brother of a very famous actress. Any guesses?
via: InstagramHis sister is Maisie Williams! Williams actually has three siblings, all of whom are older: James, Beth, and Ted.
via: GettyYou might actually recognize this celeb sib if you passed her on the street. She's a journalist and TV presenter in Australia.
via: GettyAnd she's Nicole Kidman's little sister! Her name is Antonia.
via: TwitterThis celeb sib looks like a mix between Dax Shepard and Zach Braff...but he's not related to either of them. Nope, this guy (his name is Doug) is the younger brother of...
via: TwitterBrad Pitt! Doug is a Goodwill Ambassador for the United Republic of Tanzania. The Pitts also have a sister named Julie. OK, this next one is a little easier...
via: InstagramThis woman has a famous sister, but she's also forging her own path to fame as a fashion designer. Any guesses who's blocked out on the right?
via: InstagramLady Gaga! Her little sister's name is Natali Germanotta. She actually made an appearance in Lady Gaga's music video for "Telephone."
via: GettyThis guy you might actually recognize. He took part in a very famous selfie.
via: GettyIt's Lupita Nyong'o's little brother Peter. Remember the famous selfie Ellen took at the 2014 Oscars? He made it into the photo! (He was wearing glasses at the time, so no judgment if you didn't recognize him at first.)
via: GettyThis isn't just a celebrity's brother. He's a celebrity's twin brother. (They're fraternal, obvs.) So who's his sister? I'm glad you asked...
via: GettyIt's Scarlett Johansson! Her twin brother's name is Hunter. The two also have an older sister, brother, and half-brother.
via: TwitterHere's another celebrity twin! Can you guess the celeb?
via: TwitterIf you guessed Ashton Kutcher, you're absolutely correct (and I'm super impressed)! Ashton's twin brother is named Michael. The two also have an older sister named Tausha.
via: TwitterHere's our last celebrity sibling. Any guesses as to whose brother this might be?
via: TwitterYep! Zac Efron! That's his brother Dylan. He just ran the Boston Marathon! Share this with your sibling — make sure to let them know which one of you is the "famous" one.