Robert Downey, Jr.: Risk Level 'High'

With one cinema blockbuster ("Iron Man") already under his belt this summer, Robert Downey Jr. is preparing to wow audiences and critics with "Tropic Thunder," a comedy in which he plays a white actor playing an African-American character in a film.

After a high-profile addiction struggle, Downey is back on Hollywood's A-list, and the new film is receiving good reviews. But Downey said his ups and downs with success aren't a sign of vulnerability.

"I've never taken it all that seriously to begin with," he said on "Good Morning America" today. "I think of it as kind of an athlete. You get a Super Bowl ring. It's great. The season's over. Now, try to do it over again, and it doesn't happen."

Robert Downey Jr.Play

Downey's take as A-list, Academy-Award winning actor Kirk Lazarus in "Tropic Thunder" allowed the veteran to show off his comedic chops while simultaneously making fun of his fellow thespians.

In the film, Lazarus is so committed to his role as an African-American soldier during the Vietnam War that he changes his skin pigmentation to make the character more real. While Downey said he was pleased when the film's lead actor, director and writer, Ben Stiller, approached him to be in the film, he did have some reservations.

"I thought a couple things. I thought this could be a really bad idea. And as I read more, I thought it was an opportunity to kind of to do something to show that we've progressed to a point where what used to be so hurtful and offensive could now be used in a self-deprecating way," Downey said. "I also thought, 'How come Ben Stiller calls me and asks me to be in a big comedy movie but makes the risk level this high?'"

Even in 2008, the idea of a white actor in black face could be deemed offensive, but Downey said he took care to make sure the character, premise and jokes didn't cross the line.

"Where's the border between what's funny and what's actionable? I think it always comes down to, in your own heart, in your own moral psychology, do you feel that you can represent something without being offensive? I don't think comedy needs or should be offensive. I think it can be a little bit borderline. But if it's appropriately managed, it's entertaining," said Downey.

"It took a lot of creative discussions to have everything turn out right," Downey added.

The Making of 'Tropic Thunder'

Downey is just one of the heavy hitters that appear in the film's ensemble cast, which includes Tom Cruise, Nick Nolte, Jack Black and Matthew McConaughey — not to mention the stars that make cameos in the picture.

Downey said Stiller's script was what drew so many people to the film, and the actors did do a lot of ad-libbing, too.

"I'd say probably about half the script was really good. That's what got everybody involved. We're out in the jungle doing this crazy comedy with Ben marching us around, dressed like a soldier [with his] swollen arms and saying, 'Boy, I hope this turns out. This is a potential career destroyer,'" Downey joked. "I thought, all the goodwill from 'Iron Man' and I'm going to get tanked now."

His career is intact and this film likely only will boost his popularity. But for Downey, filming the picture wasn't all fun and games.

"I'm the only one in special-effects makeup sitting out there in 90-degree heat at eight in the morning," he said. "And it kind of smelled like wild boar urine [everywhere we went.]."

Downey's co-stars joked yesterday on GMA that what was ironic was that he was playing a diva and yet acted like one on the set. But Downey said there was only one reason for the dis — jealousy.

"I was more handsome than all of them. I was a beautiful black man and they weren't," he joked.