Katy Perry's Surprise London Appearance

Katy Perry surprised U.K. fans on Thursday by popping in for a sneak preview screening of her new film unannounced.

RELATED: Katy Perry Retraces Her Journey in Upcoming Film

The pop star sat smack dab in the middle of an audience filled with excited teens while Katy Perry: Part of Me played on the big screen of the Apollo West Theater in London.

The 3D movie is an intimate look at the artist's career, lifestyle and philosophy, giving viewers a deeper understanding of where she came from and where she's headed.

Part of Me, which has not yet been rated, opens July 5.