zefron041911_08-full-1230WM.jpgZac Efron car shots

Zac Efron is single and definitely ready to mingle!

Question is ... who's the girl that left Trousdale with Mr. Efron last night? Seems as though the two were trying to fly under the radar. No such luck.

The sexy actor's new lady friend is certainly sassy. See her flipping off the cameras ... after the jump.