Jake Gyllenhaal still can't talk about Heath Ledger's death

Los Angeles - Jake Gyllenhaal can't articulate how he was affected by Heath Ledger's death.

The 35-year-old actor was devastated when his friend and Brokeback Mountain co-star passed away from an accidental overdose in 2008 and the tragedy impacted both his personal and professional life.

He said: "Personally, it affected me in ways I can't necessarily put in words or even would want to talk about publicly.

"In terms of professionally, I think I was at an age where mortality was not always clear to me."

Heath's death taught Jake that success is "fleeting" and the relationships he makes on movie sets are for more important than the finished films.

He told interviewer Jess Cagle: "I think you live in this bubble, too, of making films ... There are real friends, and there is a real community.

"There is also that new Macklemore song where he says, 'The curtain closes and nobody notices' ... I think that's true, and I think that's OK.

"But I think at the time, I assumed everyone would notice - and they did with Heath dying, but I think it [gave me] the experience of, 'This is fleeting.'

"And none of the attention or synthesised love that comes from the success of a film really matters at all. What matters is the relationships you make when you make a film, and the people you learn from when you're preparing for a film. That changed a lot for me."

Both actors scored their first Oscar nominations for the movie, but they had no idea how successful it would be at the time.

Jake said: "We were super young. We had no idea what the movie was going to become."