Having Fun, R-Patz?

R-Patz has got a mayjah case of the giggles!

Did someone take a big toke of the good shiz before hitting the stage???

Pattinson joined his fellow New Moon co-stars for the first day of the Twilight mall tour on Friday at the Hollywood and Highland Center in El Lay, and R-Patz could not keep a straight face!

Puff, puff, pass!

[Photo via Getty Images.]