"As Marlon once so beautiful f**king said to me, 'Life is a birdsong'. That's stuck with me," he told Details magazine. "For everybody, the clock's ticking. The main thing is whether you sit there and stare at the clock in fear of your ultimate demise - which is pointless - or you just live."
Depp believes he has reached the "really satisfying" stage that Marlon got to when he "just didn't give a f**k".
• Read more: Johnny Depp shocks awards with 'slurred and stumbling speech' (+vid)
"First, I reached a point where I cared so much and was so diligent in terms of approaching the work," he said. "Then you get to where you care so f**king much that it gets goddam beleaguering, you know?
A scene from Dark Shadows.
"But then a great thing happens. Suddenly you care enough to not give a f**k because not giving a f**k, that's the total liberation. Being game to try anything."
Depp is acutely aware that the success of Pirates, in which he plays the Keith Richards-inspired Captain Jack Sparrow, will be hard to live up to.
A scene from Pirates of the Caribbean.
"It's like being a dog at the track. They expect you to live up to some race you happened to be in and won accidentally," he continued. "From that first second, you're nothing more than a commodity. They have expectations of another Pirates.
"It's great if something works, boy, that's killer. But God, to have that as your design...it's ugly, I think."
Johnny Depp at the Hollywood Film Awards. Photo / AFP
Depp shocked the Hollywood Film Awards audience earlier this month when he stumbled, slurred and swore his way through a speech before blaming his erratic behaviour on it being "one of those nights".
He will next be seen playing the Big Bad Wolf in darkly humourous musical Into the Woods, due in New Zealand cinemas on 8 January.
A scene from Alice In Wonderland.
Depp's other forthcoming films include Mortdecai, Black Mass and Alice In Wonderland: Through The Looking Glass.
- Independent