Lady Gaga is set to appear in the upcoming movie "Sin City 2: A Dame To Kill For."

The singer surprised fans when she popped up in the new trailer for the Robert Rodriguez movie on Monday.


 The clip shows her in a short scene with star Joseph Gordon-Levitt, playing a waitress in a 50s-style diner.

 The Mother Monster confirmed the news on her Instagram, as well.  


She called Gordon-Levitt her "favorite scene partner" and says Rodriguez "really killed this one."  Gaga also responded to a fan question on Twitter, saying she's "not a big part" of the "Sin City" sequel, but is "always happy" to be included. The singer also had a cameo role in Rodriguez's "Machete Kills" last year.