Jake Gyllenhaal - Gyllenhaal's Challenge To Sister Maggie's Suitor

JAKE GYLLENHAAL made life hell for co-star PETER SARSGAARD on the set of JARHEAD, to make him prove he was worthy enough to date his sister MAGGIE.

The pair had just begun dating when shooting started on the first Gulf War drama, and Gyllenhaal was determined to put his co-star to the test.

He says, "I considered that it was him trying out for my sister's hand. I'm not saying whether he succeeded, but that's what it was. I think Maggie revelled in it - I think she was excited for both of us.

"And we came out of it closer, that's for sure."