The former High School Musical hunk, who is reportedly dating actress Lily Collins, was reaching the end of the press line as he promoted the animated family film at Universal Studios Hollywood on Wednesday (22Feb12) when the blunder occurred.
Video footage of the incident, which has since surfaced online, shows Efron reaching into his trouser pocket to hand something to his assistant when a shiny gold condom-sized packet also pops out and falls to the ground.
The red-faced 24 year old immediately reached down to swipe the item - but the mishap was already caught on camera.
He was spotted mouthing, 'Oh, my God!' as he turned his back to the cameras.
Efron's movie co-stars Taylor Swift and Danny DeVito were also in attendance at the premiere.