WHITE OUT: Carrie Fisher has admitted snorting cocaine on the set of The Empire Strikes Back.

Carrie Fisher's drug habits were in full swing as she battled Darth Vader's forces playing Princess Leia in The Empire Strikes Back.

Not until surviving an overdose six years later did the young actress realise the extent of her own dark side, a spiralling drugs problem that would come to characterise much of her life.

"We did cocaine on the set of Empire, in the ice planet," Fisher reveals.

"I didn't even like coke that much, it was just a case of getting on whatever train I needed to take to get high."

During that same year, 1980, Fisher played the part of a manic ex-girlfriend in The Blues Brothers alongside her then boyfriend Dan Ackroyd and John Belushi.

One of Hollywood's most infamous stories of excess, Belushi recognised Fisher as a kindred spirit and brought her into his inner circle prior to his death from cocaine and heroin.

"Hanging out with them didn't help and John actually recognised it in me," she remembers.

"He said to me once, 'You and I, we're alike, we're not like them', referring to his wife and Danny (Ackroyd).

"Slowly I realised I was doing a bit more drugs than other people and losing my choice in the matter."

Now 53, Fisher can see the funny side of her battles with addiction and has channelled her experiences into an award-winning stand-up show Wishful Drinking, which visits five Australian cities throughout October and November.

Uncovering a life which has slipped several times between sobriety to relapse, the author says a light hearted approach has reasserted a sense of control despite many subjects continuing to prove difficult to laugh at.

"It wasn't funny when a friend died in my bed from an overdose and it took a long time for that to be ... It's not funny still, but it's funnier, and not as tragic.

"Mental hospitals and rehab can be funny while you're there, in fact they'd better be," she asserts knowingly, before recounting a story of a friend who shot herself in the head during her second stint in rehab.

Wishful Drinking is not a form of ongoing therapy - "that would be selfish" - and instead it offers audiences a chance to question the former pin-up actress, more recently a novelist, chat show host and script doctor, on anything and everything.

The artwork to the tour depicts Princess Leia slumped face down, her famously coiffured hair buns surrounded by pills and an empty martini glass, but ironically alcohol never passed Fisher's lips in the same amounts as other intoxicants.

If it had done, perhaps Return Of The Jedi might never have been made.

"The stuff I liked was very hard to get hold of, if I'd been addicted to booze I'd be dead now because you just go out and get it.

"Because my drugs were illegal, or the amounts I wanted to do were illegal, it made it more difficult for me to get in trouble."

Fisher was born into showbiz as the daughter of movie star Debbie Reynolds and Eddie Fisher, who famously walked out on the family to marry Elizabeth Taylor.

She acknowledges the relationship with her father, who died last month, was never perfect but refuses to blame either her celebrity upbringing or fame for her descent into drugs.

"It's always been my responsibility, if it was Hollywood then we'd all be dope addicts," she says, declining to divulge which of her Star Wars co-stars joined in with her high jinks.

"Being Leia was not a problem for me, it was funny even if it did require a lot of adjustment.

"I mean I was a stamp. Nobody gets to be a postage stamp."