"My summer resistance training - the sea resists me and it's winning," he captioned the post.

According to the insider, the hard-working star hits the gym every morning using a variety of weight machines and free weights to try to build up his biceps, shoulders, chest, legs and glutes.

"He's desperate to build himself up, targeting every area of his body. It's exhausting but he's going for it," the source shared.

He also does tons of cardio on the treadmill, stationary bike and stair climber, and jumps on boxes and the mini trampoline.