Pop diva Rihanna is totally unrecognizable in her first acting role as a soldier taking on some scary aliens in the upcoming 'Battleship.' Gone are the wild wigs and barely-there outfits; instead, she's in a uniform and wielding some badass looking artillery.

Although she's in pretty amazing shape (as those skimpy stage costumes clearly show), she had to undergo intensive military training for the role.

"We worked with real military people ... people in the Navy, people who have fought in Iraq before," Rihanna explained. "This one man, Donald, he pretty much drilled me, yelled at me, cursed me, made me do push-ups... I really wanted to say, "F**k you" right back, but then he probably would have thrown me through the window! I was so scared. I just stood there and looked at him like, 'I swear I'm going to get it right, I swear, I swear, I swear I'll be good.'"