Fresh from Iron Man, Robert Downey puts on an even more surprising performance in Hollywood spoof Tropic Thunder. He talks to Peter Mitchell

Key Points:

Robert Downey Jr has become the master of the "layered" performance.

In his last big movie - Iron Man - he played an industrial tycoon who wrapped himself in metal.

In his next one, this American actor is playing an Australian actor who is playing an American character - and an African-American character at that. Well he's always enjoyed a challenge.

The 43-year-old actor has overcome plenty, whether it was his battle with drugs in the 1990s and early 2000s that landed him in jail, or roles few actors could pull off, such as his best actor Oscar-nominated performance in Chaplin.

When Ben Stiller phoned him a year or so ago, Downey wondered if he had finally met his match. The role Stiller was offering Downey was an odd one.

It was for the action-comedy Tropic Thunder co-written and to be directed by Stiller.

Stiller was targeting Downey to play the character Kirk Lazarus, a hardcore, Aussie method actor. Mastering the accent was the easy part.

The great challenge for Downey was he not only had to play ocker Lazarus, but also play Lazarus portraying an African American army sergeant, Lincoln Osiris.

Confused?

So was Downey.

"Yeah, sure I was," the actor laughed during an interview at a West Hollywood hotel recently.

Tropic Thunder is a spoof of Platoon, Full Metal Jacket, Hamburger Hill and other 1980s Hollywood films set during the Vietnam War.

The story follows a group of pampered, self-obsessed actors, including Lazarus, as they attempt to shoot a war movie in a jungle in South-East Asia.

The actors stumble into an area controlled by a drug syndicate, but are so self-absorbed they do not realise the heavily-armed traffickers who chopped off their director's - Brit funnyman Steve Coogan - head are the real deal.

They think they are other actors and it's all part of the movie.

Stiller, who also stars in Tropic Thunder, recruited Jack Black into the squad and there are supporting turns from Nick Nolte, Matthew McConaughey, Tobey Maguire, Jon Voight, Alicia Silverstone and a surprising cameo by an unrecognisable Tom Cruise.

While Stiller mercilessly pokes fun at Hollywood in the film, he's in hot water with disability groups in the US for the repeated use of the word "retard" in one scene.

Downey also knew he was treading in sensitive territory as white Australian Lazarus playing African American Sgt Osiris.

"There were times I was a little freaked out where I thought `If I do this wrong it's kind of my fault'," Downey said.

Downey's Lazarus, who some believe is modelled on Russell Crowe, is a five-time Oscar winner and is so dedicated to pulling off a believable performance as Sgt Osiris he undergoes an operation to darken his skin.

Downey is hopeful African Americans will not be offended.

"If you see the movie, it's a non-issue," he said. "If you read the script, initially you would say `This is probably a non-issue', but there's a lot of things that have to be managed and handled correctly down to the look and execution."

Tropic Thunder, dubbed by some American critics as the funniest film of 2008, will continue a golden year for Downey if it lives up to the hype.

Not too long ago Hollywood studios and directors deemed Downey a liability because of his drug history, but this year he clawed his way back to the top of the industry with the success of the action film, Iron Man.

In October, he begins Sherlock Holmes with director Guy Ritchie in London.

Seven years ago if Downey's photo was in a newspaper, it was likely one of his many police mugshots.

In April 2001, he was arrested when police found the actor wandering dazed in an alleyway after midnight in a seedy area of west Los Angeles. He was arrested on suspicion of being under the influence of a controlled substance. A urine test detected Downey had cocaine in his system.

Five months earlier police found cocaine and methamphetamine in his Palm Springs hotel room.

Just three months before the Palm Springs bust, Downey had walked out of Corcoran state jail, located in the desert three hours north of Los Angeles.

An exasperated judge sent him to the jail for repeatedly violating probation for a 1996 arrest for drug possession, driving under the influence and carrying a concealed weapon.

Rehab and close friends, including Mel Gibson, who has had his own brushes with the law and an addiction problem, helped Downey through it. The actor also found stability with his 2005 marriage to film producer Susan Levin.

Downey says his life is now structured, with martial arts and tennis helping him control his dark side. He is enjoying being back at the top in Hollywood.

There's two Iron Man sequels in the works that will earn him a reported US$30 million ($43 million)-plus and the feeling in Tinseltown is he will finally be rewarded with an Oscar in the next few years.

But the actor isn't getting carried away. He knows the demons of seven years ago are lurking nearby.

"Sometimes you have to be careful what you wish for."

LOWDOWN
Who:
Robert Downey Jr as Kirk Lazarus, a Russell Crowe-ish Aussie playing an African American GI Lincoln Osiris in a Vietnam War movie. For laughs.
What: Tropic Thunder, also starring Ben Stiller (who directed), Jack Black, Steve Coogan and a cameo from Tom Cruise
When: Opens at cinemas today.

- AAP