Naomi dons a mask in this photo form 90210. But the secret is out: we can totally tell it's her!

Dhana Taprogge performs here on 90210. She's a musical guest on the first episode in April 2013.

Annie is Author X. She is forced to own up to this fact on the episode "A Portrait of the Artist as a Young Call Girl."

Pictured in this scene from 90210: Grant Gustin as Campbell and Matt Lanter as Liam.

Navid and Silver cozy up in this photo from 90210. It's courtesy of the episode "A Portrait of the Artist as a Young Call Girl."

Annie's secret identity as Author X finally comes out on 90210. "A Portrait of an Artist as a Young Call Girl" is the 18th episode of the show's fifth season.