While it's pretty sweet to be a celebrity (the fame, the fortune!), there are definite downsides to being a celeb. Who can you really turn to other than your non-celeb friends... or your celeb "friends"? Ah, the beauty of having someone who completely relate to you - especially when it comes to your siblings! Some of the hottest celebs have more than one celeb in the famiy, from Chris and Liam to Jessica and Ashlee to Lindsay and Ali. Sibling rivalry? Nah! Here are 15 celebs who are related as siblings!