"When anything is blocking my head or there’s worry in my life, I just—whoosh—go sit on Mars or something and look back here at Earth."

That's what an up-and-coming talent named Heath Ledger told Vanity Fair magazine in 2000, before he became one of Hollywood's most respected actors, and eight years before his untimely death at age 28.

Now, a year-and-a-half after Ledger's January 22, 2008 death, Vanity Fair has talked to scores of Ledger's friends for its August 2009 issue, trying to piece together his final days and how Ledger may have come to take the lethal combination of drugs that led to his death.

PHOTOS: Click for new exclusive Vanity Fair photos of Heath Ledger's final days.

"Everyone has a different view of how he passed away," said vocal coach Gerry Grennell, who worked and lived with the actor during the filming of The Dark Knight. "From my perspective, and knowing him as well as I did, and being around him as much as I was, it was a combination of exhaustion, sleeping medication … and perhaps the aftereffects of the flu. I guess his body just stopped breathing."

Terry Gilliam, who directed Ledger in his final film, The Imaginarium of Doctor Parnassus, put part of the blame on his divorce from wife Michelle Williams.

"Because he’s a much nicer person than I am, he really thought he could do the right thing. He was trying to be decent and graceful, give her whatever she wanted—the house, every f*cking thing," said Gilliam. "But once it started going south, it went very quickly. He was overwhelmed by lawyers, and there were more and more of them, as if they were breeding. I said, ‘This is bullsh*t. Heath, just end it. Get out—it’s bad. You’ve got to just walk away from it.’ The stakes kept going up. He wouldn’t listen to any of us."

Ledger's friend and agent Steven Alexander said the scrutiny involved with being a famous actor was at odds with what Ledger was looking for in an acting career.

"He was ready to bust out of the gate, but he didn’t want to step on the gas and become something that he didn’t want to become: a matinee idol," said Alexander. "He was a private person, and he didn’t want to share his personal history with the press. It just wasn’t up for sale. That’s part of the reason he initially tore down his career. He wasn’t motivated by money or stardom, but by the respect of his peers, and for people to walk out of a movie theater after they’d seen something that he’d worked on and say, ‘Wow, he really disappeared into that character.’ He was striving to become an ‘illusionist,’ as he called it, able to create characters that weren’t there."

More From VanityFair.com

FEATURE: Heath Ledger in the August 2009 Vanity Fair

PHOTOS: Heath Remembered: A Photo Slideshow

FEATURE: "We’re Havin’ a Heath Wave," the August 2000 cover story by Kevin Sessums