Her doting pop went all out on her gift, buying the singer a $24,000 customized Cam-Am Spyder motorcycle, complete with her initials plastered all over it.
The three-wheeled motorcycle has lately become a trendy toy among the rich and famous – The Game, Ryan Reynolds and Jada Pinkett Smith have all been seen tooling around town on them – and even Billy Ray was photographed taking the gift for a spin around his Toluca Lake neighborhood with younger daughter Noah on the back on Friday .
Cyrus also posted a few Twitter pics of a pretty floral arrangement sent by friends, and Kelly Osbourne Tweeted a shot of them celebrating with a cupcake and birthday hats backstage at Sunday's AMAs.
"Thank God she is finally legal!" Osbourne said of the b-day girl.
But the real party began when her crew – Osbourne, Emma Roberts, Liam Payne and Niall Horan of One Direction, Wiz Khalifa, Amber Rose, Cherie Daly, Tyler the Creator and the ATL Twins to name a few – hit Hollywood hotspot Beacher's Madhouse.
With performances from a professional twerk team led by Beacher's resident twerker Amazon Ashley, and Mini-Miley and Mini-Robin Thicke recreating their infamous VMA performance to mini-teddy bears and Dr. Seuss's The Lorax, guests were not disappointed. They were also treated to a cake depicting the singer in a bikini made of pot leaves.