Actor Jake Gyllenhaal can proudly tell the difference between the Army and the Marines, after starring in new war action film JARHEAD

The DONNIE DARKO star enjoyed learning about life in the marines and likes the fact that he can point out the difference between the US forces himself.

Gyllenhaal, 24, says, "Before I did Jarhead I wouldn't have known the difference between the army and the Marines. But now, every time someone asks me about being in the army, I'm like 'It's the Marines.'

"I actually ran into these guys in Los Angeles and they asked, 'Are you in that movie, Jarhead?' And I was like, 'Yeah.' They said. 'We're in the Marines in STA 2/7,' which was the company my character was in! We sat there and talked for 45 minutes.

"I feel I got to be part of it without having to go through the horrors that they go through, and I'm so appreciative of that."