She may only be sixteen but Miley Cyrus looked all grown up promoting her autobiography yesterday.

The teen queen beamed professionally at the hordes of girl fans who swarmed a New York bookstore for a glimpse of the Hannah Montana star.

The line outside Barnes & Noble on Fifth Ave. stretched around the block as early as 5 a.m., nearly 12 hours before the superstar started signing copies of her memoir Miles to Go.

In her book, the Disney star confessed she used to get bullied because of her father Billy-Ray's showbiz past.0

Miley was accompanied by her little sister Noah on the promotional trip.

See Miley promoting her book below