Jake Gyllenhaal struggled to have fun at this year's (15) Venice Film Festival, because he was hanging out with late actor Heath Ledger the last time he was there.

The two actors promoted Oscar-winning 2005 movie Brokeback Mountain at the Italian film event, and Gyllenhaal admits returning to Venice last week (ends11Sep15) was bittersweet - because he had fond memories of hanging out with his old pal.

The actor, whose new movie Everest opened this year's festival, tells British newspaper The Mirror, "I have a wonderful as well as a kind of melancholy and deeply sad feeling about returning here. I miss him very badly.

"Knowing that life is fragile makes you want to appreciate meaningful things and stop wasting time on things that are trivial and superficial. It made me want to be more present in everyday life and be as much in the moment as I can be."

Gyllenhaal realized how precious life is after he lost his friend, which impacted his relationships with other people, and he is now more "serious and real" with those he’s close to as he wants every moment to matter.