Last Monday marked what would have been the 37th birthday of the unforgettable Heath Ledger, who died suddenly in 2008 of an accidental drug overdose. His death rocked the Hollywood community and indeed the rest of the world, but one of the people who undoubtedly it must have been particularly difficult for was his friend and Brokeback Mountain co-star Jake Gyllenhaal.

The actor spoke very frankly about his feelings at the time in a recent interview admitting how deeply Heath's death affected him;

"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.

"I think you live in this bubble, too, of making films … there are real friends, and there is a real community,” he said. "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 okay. 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 synthesized 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."

Brokeback Mountain proved to be a turning point in the careers, and indeed lives of both Gyllenhaal and Ledger, with both actor securing an Oscar nomination for the role in the flick. While it was also on the set of this movie that Heath struck up his relationship with co-star Michelle Williams, who he went on to have a child with.

Watch the clip from the interview with People and EW editorial director Jess Cagle below...

Via EW