The 26-year-old star, who has been in rehab twice this year for cocaine abuse, needed stitches for the gash and now his mouth is wired shut, reported TMZ.
Plans to promote his new flick 'That Awkward Moment' apparently will be postponed following the incident. Efron is joined by other stars such as Miles Teller, Imogen Poots and Michael B Jordan in the comedy flick.
Last month, Efron was seen at Callaway Golf Center in Carlsbad, California during his birthday.