Ghostbusters 3 Director on Scaring Up “Perfect” Cast Mckenna Grace, Finn Wolfhard and Carrie Coon

Ghostbusters 3 writer-director Jason Reitman gushes over sequel stars Mckenna Grace, Finn Wolfhard and Carrie Coon, who play a family with a mysterious connection to the original Ghostbusters.

"I mean, what can I say without giving anything away? They're all three extraordinary actors," Reitman said at Ghostbusters Fan Fest.

"Carrie Coon, I think the first time I became aware of her was when I saw her in Gone Girl, and she kind of just stole the movie. And then I saw her in Fargo, and she just became ... you see someone and you go, 'I need to find a way to work with this person.' And you just start working towards their voice, and I started writing in her voice, because I just knew she was gonna be perfect."

At the heart of the project is Grace's 12-year-old character, a tween 'buster described in early character profiles as a "science kid" who has difficulty connecting emotionally. Leaked audition tapes, in which the girl practiced jokes to make people "feel more comfortable," suggested the character is autistic.

Reitman said he felt compelled to develop the project when he envisioned a young girl wielding a proton pack, eventually fleshing out his idea over many years.

"Mckenna Grace, I had seen her in I, Tonya — Mckenna Grace played little Tonya Harding in I, Tonya — and was just extraordinary. She was little Captain Marvel. And she came and read, [and] was spectacular," Reitman said.

"And then Finn Wolfhard, what more can I say about Finn Wolfhard than who he already is? He's perfect. It's very hard for me to articulate right now because I can't tell you anything about what the movie is about. There's ghosts, there's ghostbusting, it's also very scary."

Those same audition tapes described the 13-year-old boy character as a "conspiracy theorist" type deeply into fantasy, bringing to mind franchise architect and producer Dan Aykroyd.

Grace "loves Ghostbusters," added Reitman. "She has all these photos of her in Ghostbusters gear throughout her childhood, and she met my father [original franchise director Ivan Reitman] and she cried."

The young star impressed Reitman so much she won her role on the spot.

"We had a really sweet moment, actually. I've always seen that audition tape where [Steven] Spielberg is auditioning Henry Thomas for Elliott [in E.T. the Extra-Terrestrial], and he tells him he got the role, and Henry Thomas just starts crying. And I had a similar moment with Mckenna, where I just told her," Reitman said.

"Which is a rare occurrence, oddly, you rarely get to tell the actor face-to-face, 'Hey, you're it.' And I had that moment with Mckenna, and she just started crying. And she was so thrilled and she immediately started painting Ghostbusters paintings for our office. If you're looking for a Ghostbusters fan, there isn't a bigger one than Mckenna Grace. I'm really thrilled that she's at the center of this movie."

And of Wolfhard, whose Mike Wheeler suited up in a Ghostbusters Halloween costume in the sophomore season of Stranger Things?

"Finn's already got the training, he's worn the uniform, he seems to be ready to go," Reitman said. And Coon, "She's obviously a big fan, she's excited."

The characters, conceived with co-writer Gil Kenan (Monster House, Poltergeist), are "amazing," an excited Reitman said. "Amazing, and I can't wait to introduce you to them."

Ghostbusters 3 busts into theaters July 10, 2020.