It's been a very eventful few weeks for fans of Zac Efron without a shirt on: the actor has been hitting the beach on the Florida set of the Baywatch movie in different costumes - none of which include a top - and this week, he linked up with costar Dwayne Johnson to film what we can only assume is some sort of action-packed, muscle-filled montage of them rescuing a few kids from drowning in the ocean. Both Zac and Dwayne - along with their female costars Ilfenesh Hadera, Kelly Rohrbach, and Alexandra Daddario - kicked off filming of the '90s series adaptation last month and have been spotted looking hot while shooting their scenes. Keep reading to see their latest on-set photos!