How Cooper Hoffman Reminded Costar Judy Greer of His Late Dad Philip Seymour Hoffman: ‘Felt So Familiar’ (Exclusive)

For Judy Greer, working with Cooper Hoffman was a unique experience — but she still sometimes saw glimpses that reminded her of his late father, Philip Seymour Hoffman.

Greer, 50, plays the mother of Cooper’s teenage protagonist Ray Garraty in The Long Walk, the newest Stephen King movie adaptation that follows a group of boys participating in a contest with a gigantic reward for the winner — and a grisly end for the losers.

Despite following in the footsteps of Philip, who died at age 46 in 2014, Greer tells PEOPLE of Cooper, 22, “I was never sitting there being like, ‘Gosh, he’s so much like his dad.’ ”

“Because I only know Cooper, and he is my pal,” adds the 13 Going on 30 star, revealing that while she “never met” Philip, she was a “huge fan” of his work.

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Greer tells PEOPLE she wasn’t so much reminded of Philip’s work while watching Cooper acting — but sometimes, while they were “hanging out and off set,” she would catch glimpses.

“Cooper would make a face or something that I was like, ‘I’ve seen that face before,’ and I was like, ‘Oh, I’ve probably seen his dad make that face in a movie,’ ” she recalls.

But, Greer clarifies, “I don’t look at him and see his dad — I see Cooper. But every once in a while … as a fan of his father, having seen [him act, it was] just facial expressions, gestures, that felt so familiar to me, and then realizing why.”

Similarly, “I recently worked with Emma Thompson and her daughter Gaia Wise, and it was the same thing,” Greer continues. “Gaia is Gaia. But every once in a while, she would do a look or a gesture or something that I was like, ‘Oh my God, Emma.’ ”

As for when she first “fell in love with Cooper” as an artist, it was with his breakout role in 2021’s Licorice Pizza.

“And actually, when I saw that movie I didn’t know who his father was,” Greer says. “So I was just like, ‘Who is that kid?’ Oh my God, the charisma — it was bananas. I couldn’t take my eyes off of him.”

Directed by Francis Lawrence and adapted by JT Mollner from King’s 1979 dystopian horror novel, The Long Walk costars Mark Hamill as the Major, enforcing the totalitarian regime’s cruel rituals. Lawrence worked with Philip on the Hunger Games films.

Walkers participating in the deadly competition are played by David Jonsson, Ben Wang, Charlie Plummer, Garrett Wareing, Tut Nyuot and other young stars.

Despite their emotionally charged moments and very “not-funny” scenes in the film, when Greer and Cooper met, they “had great chemistry and loved each other and started laughing right away.”

“I feel like I’ve known him my whole life,” she says. “And technically, I probably could have known him his whole life — I didn’t, but I feel like I have. So that made it simple.”

The Long Walk is in theaters Sept. 12.