Justin Bieber felt a call of duty at West Point ... to play hockey.
The Biebs hit the ice Saturday with the official Army West Point hockey team in New York for a friendly match among cadets.
The team shouted out Justin on Twitter saying, "Bieber knows the rules ...respect the logo."
We're told Justin has had a standing invite to play. Looks like he took 'em up on it in West Point forward Nick DeCenzo's jersey.