Matt Damon "fell into a depression" when he knew he wasn't making a great movie.

The 'Oppenheimer' star - who has Isabella, 17, Gia, 13, and Stella, 12, with wife Luciana Barroso and is stepfather to 24-year-old Alexia - didn't name the production, but recalled the despair he felt at uprooting his family while he worked on a project that he realised mid-way through wasn't what he had "hoped it would be".

Speaking on YouTube channel 'Jake's Takes', he said: “Without naming any particular movies…sometimes you find yourself in a movie that you know, perhaps, might not be what you had hoped it would be, and you’re still making it.

“And I remember halfway through production and you’ve still got months to go and you’ve taken your family somewhere, you know, and you’ve inconvenienced them, and I remember my wife pulling me up because I fell into a depression about like, what have I done?”

The 52-year-old actor's wife provided Matt with encouragement and urged him to just continue to be professional and do his best because there was little else he could do.

He recalled: She just said, ‘We’re here now’.

“You know, and it was like… I do pride myself, in a large part because of her, at being a professional actor and what being a professional actor means is you go and you do the 15-hour day and give it absolutely everything, even in what you know is going to be a losing effort.

“And if you can do that with the best possible attitude, then you’re a pro, and she really helped me with that.”

The 'Suburbicon' star previously admitted he knew 'The Great Wall' - in which he starred as a mercenary warrior imprisoned within the Great Wall of China before joining forces with the Chinese to combat an alien invasion - was a "turkey" while filming the 2016 movie and realised the project was doomed when he saw how the film's Hollywood backers were pressuring director Zhang Yimou to change his vision.

Speaking to Marc Maron on his 'WTF' podcast, Matt said: “I was like, this is exactly how disasters happen.

“It doesn’t cohere. It doesn’t work as a movie.

“I came to consider that the definition of a professional actor; knowing you’re in a turkey and going, ‘OK, I’ve got four more months. It’s the up at dawn siege on Hamburger Hill. I am definitely going to die here, but I’m doing it.’”

“That’s as s***** as you can feel creatively, I think. I hope to never have that feeling again.”