Robert De Niro was surprised by the scale of the #MeToo scandal.

The 75-year-old actor found it ''disturbing'' that sex had allegedly been used as a bargaining tool for actors and actresses to land parts and he thinks he was ''naive'' to have not realised it happened frequently.

He said: ''Maybe I'm naïve. It made me aware how prevalent it was. You hear about the casting couch, but I found it hard to believe people would behave so badly to get laid.

''It's disturbing to me. When a casting person or a producer infers something could happen - if you sleep with me, I'll get you to this person - that is beyond unacceptable. Actors are very sensitive about actors. When they want a part, and if you intimate you are going to give them a part, they believe you, and if they want that part, you have to be very careful.''

And the 'Raging Bull' actor insists it was a side to the movie industry that was always kept from him.

He told the i newspaper: ''I don't witness that stuff too much and certain people are not going to tell me what they do to a person, or how they try to seduce them or use them, or harass them. They probably sense that it's not something that will sit well.''

Meanwhile, the screen legend can next be seen reteaming with director Martin Scorsese to play alleged Mafia hitman Frank Sheeran in 'The Irishman' and was delighted to turn back the clock without having to spend hours in the make-up chair thanks to advancements in technology.

He said: ''We were about to do a movie about a retired hitman in California. I read a book as part of my research called I Heard You Paint Houses by [homicide prosecutor] Charles Brandt and I said to Marty: 'Let's incorporate it into our story.' It didn't work, so we decided to make this instead.

''The idea was to go back four or five decades. Marty wanted to make us look younger. I was excited by the thought of being able to do it without the use of make-up.''

It will be the ninth time Scorsese has collaborated with De Niro, and the star admitted the role he'd most like to revisit is his character Travis Bickle from the 1976 classic, 'Taxi Driver', however they couldn't ''come up with ideas'' to make a sequel work, even though he knows there's a demand from fans.

He added: ''I thought people would be curious to see where he is today. Marty [Scorsese] and I talked to [writer] Paul Schrader, but we just couldn't come up with ideas.''