"Didn't know this was coming out yet! I'm so happy to be #1 on Maxims HOT 100! #myfanskickass #dreamsdocometrue," Cyrus tweeted Friday ahead of the list's official release.
Cyrus, 20, was the star of TV's "Hannah Montana." She has also appeared in the films "The Last Song" and "LOL."
Supermodel Bar Refaeli topped last year's Maxim Hot 100 roster.