You Won't Believe Miley Cyrus's Sister Is Only 15

Miley Cyrus's little sister is following in her footsteps in more ways than one. At 15 years old, Noah has already proven her penchant for posting surprising Instagrams. The teenager shared part of her night with a pal at Kylie Jenner's 18th birthday party on Sunday. In one snap from the photo booth, Noah pouts her lips while baring her midriff.

Noah also has the vocal chops to challenge Miley on the Billboard charts. In June, Billy Ray and Tish Cyrus's youngest child hit the stage at an open mic event in LA, unleashing a voice that might remind you of Miley's in "Wrecking Ball." Read on to see how fast Noah is growing up, and then find more celebrity kids taking over Instagram.