RPatz & KStew -- Honeymooners Sucking Face

11/8/2010 9:45 AM PST BY Johnny Lopez
Robert Pattinson and Kristen Stewart shared a big, fat, wet kiss in Rio de Janeiro this weekend ...  but it couldn't have been more scripted.


It was all for a honeymoon scene in the upcoming "Twilight" flick "Breaking Dawn."

Spoiler alert?