'50 Shades of Grey' Star Jamie Dornan -- Hey Ladies ... I'm REALLY Flexible

Welcome to the gun show ... "50 Shades of Grey" star Jamie Dornan proved his body is definitely hard core enough to play Christian Grey.

Dornan's muscles look like they are about to explode in this impressive pic of him balancing his entire body weight on a workout bench. He says he held the pose for about 2 secs before collapsing in tears. We doubt that.

If '50 Shades' fans were worried JD wasn't hot enough to pull off the role ... they ain't worried any more.