Iron Man will continue with or without Downey Jr

'Iron Man' will continue whether or not Robert Downey Jr decides he wants to sign up for another film playing billionaire playboy Tony Stark.

Marvel Studios boss Kevin Feige has said that he's got bigger plans for the Avengers linchpin in the future.

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“I believe there will be a fourth 'Iron Man' film and a fifth and a sixth and a 10th and a 20th,” he told Entertainment Weekly.

“I see no reason why Tony Stark can't be as evergreen as James Bond. Or Batman, for that matter. Or Spider-man.”

There has been much talk over whether Downey Jr will return as the Marvel Comics hero, with the actor himself casting doubt on whether he'll embark on another incursion.

Downey Jr has become staggeringly expensive since the first 'Iron Man' film in 2008, commanding a fee of $50 million (£32 million) to appear in 'Avengers Assemble'.

Co-star Gwyneth Paltrow has also said that the studio is not planning a fourth film in the current series.

Whatever the future of the character, Downey Jr's third appearance in the iron suit is coasting towards box office glory, and looks likely to bust the $1 billion mark.

It's already the second biggest US debut of all time, making $175.3 million (£113 million) on its home turf.

Worldwide takings are now in the region of $680 million (£437 million).