'I'm flexing so hard I got a cramp,' he quipped alongside the revealing pic.
Channing Tatum is baring nearly all! The 41-year-old actor took to his Instagram Story on Tuesday to share a nude mirror selfie.
Tatum snapped the pic in the makeup trailer on the set of his upcoming flick, Lost City of D. The actor is completely nude in the shot, showing off his abs and chest, and using the emoji of a monkey covering its mouth to conceal his private area.
"You know when you in the make-up trailer a**hole naked holding a towel over your junk you about to do some s**t on set that you gonna have to prepare ya mama for before she see the movie," he wrote alongside the pic.
"And yes I'm flexing so hard I got a cramp," he added.
Tatum is set to star in the romantic comedy, which is due out next April, alongside Sandra Bullock, who's also producing the flick.
In the film, Bullock plays a reclusive romance novelist who was sure nothing could be worse than getting stuck on a book tour with her cover model (Tatum), until a kidnapping attempt sweeps them both into a cutthroat jungle adventure, proving life can be so much stranger, and more romantic, than any of her paperback fictions.
Brad Pitt will have a cameo in the movie, while Patti Harrison, Da’Vine Joy Randolph, and Daniel Radcliffe round out its cast.