Typically iron-willed Iron Man star Robert Downey Jr has been unravelled by a particularly pesky interviewer whose prying questions prompted the actor to walk out of an interview.

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During an interview to promote his upcoming blockbuster Avengers: Age of Ultron, the 50-year-old lost his cool when reporter Krishnan Guru-Murthy asked him about his troubled past.

The Channel 4 interviewer began by raising a quote the actor gave to The New York Times in 2008: “You can’t go from a $2,000-a-night suite at La Mirage to a penitentiary and really understand it and come out a liberal. You can’t.”

Guru-Murthy questioned Downey Jr. as to what he meant by this statement and whether he still considered himself to be a liberal.

“Are we promoting a movie here?” Downey Jr. responded, before explaining that he couldn’t explain off-hand comments from his past.

“That’s the nice thing, you can have opinions and they change and flow.”

Guru-Murthy continued his interrogation, however, much to the actor’s displeasure.

“You say we’re promoting a movie… but we’d also like to talk a little bit about you. I don’t know how comfortable you are talking about yourself,” the anchor said.

“You have as much time as anyone else will,” Downey responded.

“Your foot is starting to jump a little bit, you better get to your next question.”

Channel 4 interviewer Krishnan Guru-Murthy.

“The reason I’m asking about the past is that you’ve talked in other interviews again about your relationship with your father and the role of all of that in the dark periods you went through, taking drugs and drinking and all of that,” Guru-Murthy continued.

“And I just wondered whether you think you’re free of all of that…”

In the past, Downey Jr. has been open about his struggles with addiction and alcoholism, which landed him one year in prison in 1999.

However, the actor did not seem keen to continue the line of questioning, interrupting Guru-Murthy to ask, “what are we doing?”.

“I’m just asking questions that’s all,” Guru-Murthy responded.

Clearly uncomfortable, Downey Jr. looked to someone off camera before the interview was promptly cut short.

“You seem okay. It’s just getting a little Diane Sawyer in here,” the star said to Guru-Murhty as he left the room.