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The former Disney sweet-tart is all grown up!

Little Miss Miley Cyrus isn't so little anymore. The Hannah Montana starlet turns eighteen today, so happy b-day! She already celebrated the big day on Sunday night at Trousdale after the AMAs, but I'm sure the singer turned actress will party it up tonight too!

Miley's come a long way these past couple of years; who even remembers her scandalous Vanity Fair pic back in 2008? Now she's hitting the clubs and going to gun ranges!

But the Hollywood starlet's personal life has been a bit more chaotic. Aside from the fact that she's been on and off with beau Liam Hemsworth as of late, Miley's parents Billy Ray and Tish are getting divorced. Rumors of Tish's infidelity with Bret Michaels even prompted the singer to swap "Every Rose Has Its Thorn" for "Forgiveness and Love" for her AMA performance this weekend.

And to top it all off, Miley's latest acting venture (The Last Song) performed poorly at the box office. I know she has LOL and So Undercover in the works, but maybe Miss M shouldn't completely give up her singing career?

In recent Miley news, the 18-year-old is not dating singer Mike Posner, they're just friends. Posner also said that "she's a nice girl, but I'm 22 and a half." Guess eighteen is still too young!

And what about Miley posing for Playboy now that she's legal? Hugh Hefner said the following to FOX News in response: "The simple answer is she is the one that you and all the other readers would like to see." But? "That person changes every month and year," Hef added.

Ah well - only time will tell. Happy birthday, Miley!

Check out our MONSTER gallery of America's Sweetheart below...