'American Idol' Brittany Kerr Hot and Dangerous

1/29/2012 4:30 AM PST

'American Idol' Brittany Kerr -- Hot and Dangerous

"American Idol" cheerleader babe Brittany Kerr is more than a pretty face -- she's a pretty face with a black belt in taekwondo!

Brittany tells TMZ she started studying martial arts in Charlotte when she was 8 (above) -- and earned her black belt after 4 years of kicking girls' and boys' butts. Brit says, "I definitely made some boys cry while sparring ... I had a killer high kick!"

Kerr is now 24 and says she's laid off the taekwondo, but still does some kick boxing to stay in shape.

Steven and Randy ... you've been warned.