Chadwick Boseman -- James Brown Feels Good!!! (And He Looks Good, Too)

"Get on Up" star Chadwick Boseman is about to blow upppppppp ... so he dressed the part Thursday at LAX and showed off his massive biceps.

Boseman ignored photogs as he made his way out of the airport, but did sign autographs for the slew of fans who followed him around.

Fresh off playing Jackie Robinson in "42," Boseman's James Brown biopic opens Friday and is getting great reviews.

We're sure Boseman is great and all, but we kind of wish they went in a different direction ...