Pop-star Katy Perry is well known for her cutesy outfits, candy-colored hair, and general adorableness. She spins lyrics with questionable subject matter into pop gold by lacing it with her sugary style, and her videos are attracting as much attention as her music.

The latest vid to debut for her single “Part Of Me”, however, takes another direction entirely with a girly Perry morphing into a Marine as rebellion towards a cheating ex-boyfriend. The transformation is shockingly convincing–due in part to her interaction with real Marines–with Perry proving there’s more to her persona than just sweetness and light. She even worked out in a real Marines boot camp, which was hard work for the singer.

The song, which includes the lyrics, “You chewed me up and spit me out/like I was poison in your mouth”, has led to speculation that it was written about Perry’s ex-husband Russell Brand, but Perry denies it, saying:

“I wrote it two years ago when I was writing and recording Teenage Dream, [but] it didn’t feel right on the record. I’d have to take out one of my other songs that [made the album] a nice, complete package.”