Katy Perry Joins the Marines in Music Video for "Part of Me"

Katy Perry debuted the music video for her new song, "Part of Me," today, and we must say, it's totally about her ex, Russell Brand! 

OK! GALLERY: KATY PERRY IS BLACK AND BLUE WHILE OUT ON THE TOWN IN LONDON 

In the video, Katy catches her boyfriend cheating on her, dumps him and joins the Marines. Now, we all know Katy hasn't joined the Marines in real life, but we do have a feeling she's toughened up quite a bit since her heartbreaking split from Russell, who blamed their breakup on distance. 

OK! VIDEO: KATY PERRY LOOKS READY TO GO TO WAR IN A PREVIEW FOR THE "PART OF ME" MUSIC VIDEO 

Not only does a short-haired Katy kick some serious butt in the video, but it looks like she had a great time shooting it. Even if she did ditch her cute, candy-covered outfits... 

Check it out below and let us know what you think!