Today is Demi Lovato's 21st birthday! To celebrate the milestone, we've rounded up 21 photos of Demi and her best friends over the years. The singer has stayed BFFs with many of her old buds, made an incredible amount of new friends, and unfortunately, lost touch with a couple along the way.

Click through to see Demi's closest friends throughout time, then let us know in the comments who you were the most surprised to see.

Don't forget to leave your birthday wishes, too!