Katy Perry trained with service members at a U.S. Marine Corps base before shooting her military-themed music video Part Of Me.

The I Kissed a Girl hitmaker, who is currently in the midst of her divorce from actor Russell Brand, shows off her new tough-girl image in the video by donning fatigues, engaging in hand-to-hand combat and marching information with other recruits - all while wielding a machine gun.

And Perry reveals she went all out to make the the clip as authentic and gritty as possible by making a trip to California's Camp Pendleton to learn from the best so she could do her own stunts.

I got a fantastic person to work me out and get meinto really good shape

She tells MTV News, "I got a fantastic person to work me out and get me into really good shape... On the actual base, I did a lot of things... Iknow how to carry my weight a little bit more".

However, there was one task Perry just couldn't master - so the director had to work around the scene with clever camera angles.

She continues, "One thing I can't do, and I hope that there are other people out there that feel the same way, is climb a rope. Oh my gosh, it's so hard to climb rope! It's all about grip and arms.

"I tried five or sixtimes on set, but I had to cheat that shot. My hands were shaking".

And she insists the whole experience has helped her cultivate a new-found respect for America's servicemen and women.

Perry adds, "This music video, as much as I was sore and exhausted, I was so educated on people in the service who I've always respected, but this time the respect goes beyond and above anything I could've imagined.

"The stuff that they go through, the loyalties and strengths that they all possess, it seems like they are seriously, not to sound weird, like the heart of America.

"I was meeting kids that were 17, 18... and they just all had their own stories... So it was really interesting".