The world's two most famous porn stars went face to face in Hollywood last night -- in more ways than one! Bow-chicka-bow-wow!

TMZ cameras were outside of Vice last night as ex-con heiress Paris Hilton came out with shrinking porn star Jenna Jameson, the ladies sharing (an almost) girl-on-girl kiss for the shooting paps. After telling the star of "Where the Boys Aren't 17" that she'd see her "in a minute," Hilton did the intelligent thing and hopped into a chauffeured limo -- no more DUIs here!

On the way to her ridiculous Rolls Royce Phantom, Jenna showed off some new ink on her shoulders, some curious lips (on her face!) and even revealed a bit more after getting into her car -- lifting up her skirt and doing a quick panty/under-boob flash before driving away.

Glad to see Paris has found some responsible friends.