Legendary casting director Bonnie Timmermann reveals how she discovered stars including Natalie Portman and Kate Winslet

Legendary casting director Bonnie Timmermann — whose career is the subject of a new documentary — has revealed how she discovered stars including Kate Winslet, Benicio del Toro and Natalie Portman.

“It’s like I am looking at somebody across my desk and in my mind there is a screen behind them and I either see them on the big screen or I don’t,” Timmermann told us of her process. “It could be a Broadway play or radio show, anything. You either see it or you don’t see it. I don’t know that I have a trained eye, but my heart kind of tells me what to do.”

While Timmermann, 77 – who recently worked on the new movie “Roofman” starring Channing Tatum and “The Very Best People” with Lili Reinhart — mostly works with trained actors, she says she can spot star power anywhere.

“I could be sitting in a car being driven back to my apartment after a movie and maybe be talking to the driver and think he may be good for a part in [a] movie. It comes from everywhere,” she said.

And once she’s found someone with the X factor, she doesn’t give up on them.

She told us that director Michael Mann initially passed on Ashley Judd for 1995’s “Heat.”

“About ten days later I [had him audition] her again,” she said, “I told her to look different and she came in and got the part. You have to believe in yourself and try your best to get your director or writer or producer to see more clearly what you see. . . . I had seen her work and I knew about her family and I said, ‘No, she is the one in my head.’”

Mann trusted her instincts so much he gave her a corner office on Park Avenue while they worked on the 1980’s hit “Miami Vice,” where she discovered future stars like Liam Neeson, Viola Davis, Bruce Willis, and Helena Bonham Carter.

At a screening of the documentary, “Bonnie,” at Sanctuary at St. Paul & St. Andrew, “Succession” star Brian Cox was heard singing her praises.

“She’s a sage,” Cox was overheard telling a guest at the event, “She’s responsible for my career.”

Cox was cast in 1986’s “Manhunter” after Timmerman saw him in a play.

The doc features testimonials from Laurence Fishburne, Sigourney Weaver, Giancarlo Esposito, director Derek Cianfrance and more — and arrives just in time, with the Academy Awards finally introducing a casting Oscar in 2026.

“James Bond” producer Barbara Broccoli, Steve Buscemi, Jake Lacy, Aidan Quinn, and more attended the screening.

“Manchester by the Sea” director Kenneth Lonnergan came by for the Q&A at the event, which also functioned as an evening to raise awareness for the Center at West Park.

Lonnergan and Timmermann are part of a group of people — including Alec Baldwin, Kyra Sedgwick, Matt Damon and more — who have been trying to save the building, which also functions as an art space, after the small congregation voted to sell it to a developer who plans to build a luxury high rise.

The Landmarks Preservation Commission will hold a hearing on the matter on Thursday, Oct. 9.