Just because Miley Cyrus had to rehearse for her American Music Awards performance on the day of her birthday does not mean that the 21-year-old did not celebrate turning legal.

The singer spent Saturday, Nov. 23, practicing her stage act for the AMAs, where she closed the show with her hit single Wrecking Ball. Backstage at the awards ceremony, she had some champagne and brought out the party hats with friend Kelly Osbourne. The Fashion Police co-host posted a photo of them with another friend on Instagram and captioned the shot, "Celebrating @mileycyrus 21st birthday back stage at the #AMAS... Thank god she is finally legal!"

Cyrus' fans created a YouTube video for their favorite singer wishing her a happy birthday. The Bangerz songstress then posted the video on her Twitter account. The clip features teens singing "happy birthday' to the former Disney star, dancing to her music and showing off their birthday cards.

The video can be viewed below.

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On Sunday night, Cyrus celebrated her birthday by partying with strippers, celebrities and a guest appearance from Dr. Seuss character The Lorax at Beacher's Madhouse at the Roosevelt Hotel. Cyrus rented out the entire theater for the special birthday/AMAs afterparty, according to TMZ.

Cyrus' birthday weekend did not start out smoothly. Her Southern California house was burglarized on Friday, Nov. 22, the day before she turned 21. The Rolling Stone cover girl discovered property was missing from the Studio City home at around 4:30 p.m. The incident occurred sometime in the afternoon when nobody was home and there were not reported injuries. The thief reportedly stole some of the singer's jewelry.

An investigation is ongoing. Cyrus has not publicly commented on the robbery.