Iron Man star Robert Downey Junior has confirmed that he will play the superhero in the fourth instalment of the blockbuster franchise, reported Daily Mail.

The 49-year-old, who had said previously that he did not want to reprise his role of billionaire industrialist Tony Stark and his alter-ego Iron Man, told Ellen DeGeneres Show on her talk show that he was doing the movie again.

Forbes named Downey as Hollywood's highest paid actor of 2014, thanks to the US$75 million (S$95 million) pay cheque he received for Iron Man 3.

Downey appeared on the show to promote his new film The Judge, which also stars Robert Duvall and Vera Farmiga.