"Don't be fooled by the rocks that she's got, she still, she still don't know how to walk..."

Jennifer Lopez put the "low" in J.Lo at last night's American Music Awards when she hit the floor dance floor, literally, after leaping off the back of a shirtless male dancer while performing her new song, "Louboutins" (see above video).

(Oh, but what a way to go!)

Luckily for the singer -- ironically dressed in a sexy sparkling boxer-inspired outfit complete with robe, gloves and boots for her "knockout" performance -- that legendary behind of hers no doubt offered plenty of soft cushioning as she bounced seamlessly back up and went on with the song.

And she wasn't the only one having a nice trip.

"American Idol" alum Adam Lambert turned his face plant into a full-on somersault (with audible thud) during his own provocative AMA performance (watch video below) -- unless that's some crazy new dance move that the kids are odign these days: called "the stop, drop and roll,"

Maybe next year these two should hire stunt doubles?

Can't resist seeing a good pratfall? Have a look at this model tumble.