Robert Downey Jr. was not first choice to star in 'Iron Man'.

The 43-year-old actor had to beg the film's director Jon Favreau to give him the lead role of billionaire weapons developer Tony Stark in the Hollywood blockbuster.

He said: "I thought I would be perfect for the part. But they weren't necessarily thinking of me right away.

"Jon Favreau said, 'Look, it's probably not going to happen.' And I said, 'Well listen, I'm not going to give up.' Which is quite unlike me. Usually I'd be like, 'I don't want to embarrass myself.' "

The superhero film, which also stars Jeff Bridges, Terrence Howard and Gwyneth Paltrow, has taken a massive $214 million at the box office since its worldwide release on April 30, prompting Marvel Studios to announce a sequel for 2010.

Robert added to US TV show 'Access Hollywood': "I'm really proud of what Jon and I did, and the fact that Gwyneth and Terrence, and Jeff Bridges all showed up for this movie.

"And I'm certain that all of us will be back to reprise our roles. It's cool. It's kind of like a really big a** series." (c) BANG