Downey Jr returns as industrialist-turned-hero Tony Stark in the third Iron Man movie, which will follow-on from last year's superhero team-up in The Avengers.
The latest Marvel film centres on Tony Stark seeking revenge on a villain known as The Mandarin (Sir Ben Kingsley), who has wreaked havoc on his personal life.
Gwyneth Paltrow and Don Cheadle are returning for Iron Man 3 as Stark's love interest Pepper Potts and best friend Colonel James Rhodes respectively.
Guy Pearce has joined the ensemble as the creator of the dangerous Extremis virus, Aldrich Killian. Vicky Cristina Barcelona's Rebecca Hall has also been cast as Dr Maya Hansen.
Downey Jr recently hinted that he is open to playing Tony Stark beyond Iron Man and The Avengers 2, saying: "I'm not stupid, I like to play ball, I love the company, I love the character, and the business side of things, I'm not too picky about that either."
Iron Man 3 opens in UK cinemas on April 26, following in the US on May 3. Watch a trailer for the film below: