Zac Efron — It’s Gut Check Time

0508_ZAC_EFRON_bauergriffinZac Efron proved he”s got game … by flaunting his jacked-up rock hard chest on the set of his new flick.

With his shirt casually unbuttoned all the way, the toned 25-year-old stud played some basketball — and showed off his ridiculously sculpted pecs and abs — while filming “Townies” in L.A. on Tuesday.

Last month, Zac injured his right hand on set … but everything appears to have healed quite beautifully.

Zac may be the one with the ball, but it”s everyone else who has to worry about dribbling.