'Breaking Dawn' -- Half Naked Lauren Pope Hangs Out at London Premiere

Robert Pattinson, Taylor Lautner and Kristen Stewart all hit the red carpet at the London premiere of "Breaking Dawn" last night ... but it was some half naked model/reality star who stole the show.

The chick sporting the side boob ... side hip ... side leg ... is Lauren Pope.

No, she's not in the movie ... but damn -- maybe she should've been.