Despite a 12-year age difference, these two celebs must have found some common ground, as they've been known to be close for more than a year. Just last month, the pretty pair was spotted hanging out together at Beacher's Madhouse at Hollywood Roosevelt Hotel. But their friendship is more than just a late-night affair. In a letter celebrating Lovato's February cover of Seventeen magazine, Kardashian wrote, "Demi, thank you for always being a true friend, for always following your heart, and for being an inspiration to me and countless other girls around the world." Enough said.