Miley 'julia' Cyrus

Miley Cyrus dressed as Julia Roberts for her 17th birthday party.

The 'Hannah Montana' star dressed as Julia's prostitute character Vivian Ward from the movie 'Pretty Woman' at an 80s-themed celebration at New York's Canal Room on Wednesday (18.11.09).

The singer-and-actress - who celebrates her birthday on Monday (23.11.09) - was particularly delighted with the evening's entertainment, a performance from Constantine Maroulis and the cast of Broadway musical 'Rock of Ages'.

A source told New York Post newspaper: "Miley had seen the show two weeks ago and loved it, so her mom Tish brought the cast in to surprise her. But I'm not sure who was more into Constantine - Miley or her mother.

Miley 'Julia' Cyrus

"Between songs from the musical, Miley grabbed Constantine and danced with him at the front of the stage and then Tish joined in."