Zac Efron [1] stepped out on the Georgia set of Dirty Grandpa on Tuesday, and all he was wearing was a pair of nude underwear. We thought we'd reached our peak of Zac perfection when he emerged in a crop top on Monday [2], but clearly, the undies take the cake. Zac has been getting back to work in the wake of a little downtime with his new, talented girlfriend, Sami Miró [3]. The two kicked off their April with a sweet trip to Mexico [4], spent time together on the night of the MTV Movie Awards [5], and made a recent smoothie run in LA [6]. Keep reading to see Zac's latest on-set pictures, and then melt over Zac and Sami's cutest snaps [7].