Robert Downey Jr has said he hasn't ruled out another Iron Man sequel.

The star first played the role of Ton y Stark in 2008's Iron Man and reprised his role in Iron Man 2 and 3, as well as the Avengers movies.

Now he has told Entertainment Weekly that there is a chance he could take on the role in a fourth movie.

"It's down to [Marvel Studios president] Kevin Feige and [Marvel Entertainment CEO] Isaac Perlmutter and Disney to come to us with what the proposal is, and that's on us to agree or disagree," he said.

"When things are going great, there's a lot of agreement."

He said of the success of Iron Man and the Avengers: "Right now, this has just been swell, hasn't it? This has been a really good one and it feels good and we're having a good time.

"It's that thing of: Why give up the belt when it feels like you can barely get jabbed?"

But he added cryptically: "Most people are saying that right when they get knocked out... The future is, as usual, uncertain."