John Krasinski doesn’t usually fret about reviews. But for his new film “IF,” he is terrified of the response from two people: His 7 and 10-year-old daughters.

“I’ve never been worried about two reviews more in my life,” Krasinski told The Associated Press in a recent interview. “I’m genuinely terrified. I hope it goes well.”

“IF,” about a young girl (Cailey Fleming) and her neighbor (Ryan Reynolds) who can see everyone’s imaginary friends including those that have gotten left behind, is one of this summer’s major studio releases opening on May 17.

In a landscape full of brands and franchises, it’s the rare original idea that has the backing of a big studio, Paramount, and an ambitious scale and scope.

It was shot largely in New York by Oscar-winning cinematographer Janusz Kaminski and blends live-action and animation with an army of celebrity voices including Steve Carell, Phoebe Waller-Bridge, Matt Damon, Jon Stewart, Maya Rudolph and the late Louis Gossett Jr.

The idea to make a film about imaginary friends started and evolved with his kids, whom he shares with actor Emily Blunt (who also voices a character). At first, it just sounded like a fun, family friendly idea.

“My kids are extremely imaginative,” Krasinski said. “I always used to say to Emily, ‘I just, I wish we could go wherever it is they go, just for a little bit.’”

Paramount agreed and in October 2019 signed on to help make and distribute the film, with Krasinski and Reynolds’ Maximum Effort. Then the pandemic hit and like so many parents of young children, he saw his daughters’ worlds alter dramatically.

“They started asking questions like, ‘Are we going to be okay’ and ‘what’s going on?’ I got so panicked. I just said, no way, we’ve got to do something about this,” he said. “That’s when it hit me to make this movie about something a little bit more, a little bit deeper than just imaginary friends.”

When he started to look into the psychology behind imaginary friends, he began to understand that these weren’t just whimsical creations. They were in fact coping mechanisms to “metabolize” daily life, whether it’s bullies at school, a divorce at home, a projection of dreams and ambitions, or any number of stressors that find their way into young minds. He understood it now as a sacred place.

“Once I realized that we were dealing with some high-level stuff, some highly imaginary, flammable stuff, I was like, this is really, really exciting,” he said. “I knew we were on to something special, and I just wanted to take it as seriously as I could.”

DIRECTING WITH FIGMENTS OF THE IMAGINATION

To play the young girl, Bea, Krasinski cast 15-year-old Cailey Fleming (she’s now 17), an actor who “Walking Dead” fans will know as Judith Grimes. She’d just wrapped season 11 of the show and was getting ready to take a break and go back to high school when she got the call that Krasinski wanted her to audition.

“I’ve never had a lead role in a movie,” Fleming said. “I was so nervous. But I couldn’t have asked for a better cast or crew.”

On a set where most of the characters would be added in post-production, Krasinski took pains to ensure that they weren’t just acting with tennis balls as stand-ins. Sometimes he’d have puppets, or a picture, or even a friend to be Carell’s character, Blue. Other times he’d just jump in and do it himself (in addition to directing and playing Bea’s dad).

“Cailey is Meryl Streep-level. She could have acted with a hot dog on a stick,” Krasinski said. “I’ve been there, I’ve acted with the tennis ball. You just try to create a world where everyone feels not only safe and excited, but also feels like their imagination takes over.

“My job as a director is to try and make every day feel like you’re doing a play rather than a movie, that it feels intimate and it feels for today only,” he added.

Many of the starry voice actors are people whom Krasinski considers friends. He wasn’t sure how they’d respond to his idea, but he said he got some of the quickest “yesses” in his career whether they had kids or not.

“It’s about this little girl but it has adults asking when they gave up on their imaginary friends and imaginations and dreams,” he said. “The beauty of the movie is it tells you that all you’ve got to do is turn around and you can always go back.”

Recently a friend of his said “IF” reminded them of “Some Good News,” the popular web series Krasinski started during the pandemic. He hopes that like “Some Good News, ”IF” is something that can bring people a little joy.

GIVING UP ‘A QUIET PLACE’

Taking on “IF” also meant passing the torch on the new “A Quiet Place” prequel. “A Quiet Place” helped put Krasinski on the map as a filmmaking force and its sequel was an early and important boon to struggling movie theaters during the pandemic. But between “IF” and the “Jack Ryan” show, something had to give.

He’d developed a story about the first day of the invasion in New York City, and sought out “Pig” filmmaker Michael Sarnoski to see if he was interested.

“(John) really helped me early on. Then he let me run free and explore things,” Sarnoski said. “He came to set the first day and sort of passed the baton symbolically. I got really lucky that he was like, ‘Hey this is a Michael Sarnoski film. Make this your own.’”

Far from being bittersweet, Krasinski said it’s exciting and an honor “to have created a sandbox that anyone can play in.” Another big summer release, “A Quiet Place: Day One” opens in theaters on June 28.

Both films he’s done in partnership with Paramount, a studio he credits for trusting and supporting his vision.

“Once ‘IF’ became more emotional and had more of a backbone to it, I think they leaned in even further. Some studios would go like, ‘Oh, no, we want the zany version,’” Krasinski said. “I think because ‘A Quiet Place’ had that same backbone, that same emotional motor, they just said, ‘Go do what it is you’re seeing in your head.’”

Krasinski has just put the finishing touches on “IF,” which means that his daughters will be seeing it very soon. They’re planning to do “a little family premiere.”

“We’re going to get all dressed up,” he said. “Basically we’re going to pretend it’s their own special premiere. Don’t tell them that it’s not the real thing.”