Jennifer Lawrence told Darren Aronofsky he has "severe psychological problems"

Speaking at a press conference for the film at the Toronto International Film Festival (TIFF) on Sunday (10.09.17), she said: "It was an instant yes before I even read anything. He told me his ideas and I thought they were brilliant and unique and challenging. I've been a fan of his for years -- I think he's bold and brave, and I think I said brilliant.

"But I've been a fan, so once he told me the ideas floating around in his head I said yes. Then I got a script and when I read it I threw it across the room and told him he had severe psychological problems. But it's a masterpiece."

Despite the tense nature of the film, Jennifer - who plays the pregnant wife of Javier Bardem's poet character - insists she had no problems shaking off the dark role at the end of the day.

She said: "I don't really carry a lot around. Between 'action' and 'cut,' I like to shake it off and not dwell in a horrible place."

But the Oscar-winning actress did admit it took her two days to overcome feeling starstruck by her beautiful co-star Michelle Pfeiffer, 59.

She said: "I love Michelle. It took me two days to get over her beauty, and to go up to her and say hi. She's very normal. She's a mother. She's a very smart woman."