‘Project Hail Mary' directors reveal how they got Meryl Streep's cameo

Project Hail Mary has delivered one of the year’s most unexpected delights: a surprise cameo from Meryl Streep.

The Ryan Gosling led sci fi epic features the three-time Oscar winner as one of the pre-programmed voice options for Rocky, the spidery alien who becomes Gosling’s unlikely ally.

Co-directors Phil Lord and Chris Miller explained that the idea began as playful improvisation on set.

“When we were on set, we did a bunch of silly voices ourselves,” Miller told Entertainment Weekly. “We had people from the crew do voices just to make Ryan laugh and have the characters have something to react to.”

But then came the spark!

“Wouldn’t it be fun to get Meryl Streep?” Lord recalled, laughing at how long they procrastinated before finally asking.

The connection came through producer Amy Pascal, who had worked with Streep on The Post.

Once approached, Streep was not only willing but enthusiastic.

“She was so fun and thoughtful and playful and did a million different versions,” Miller said. “She’d say, ‘I’ll do more. You want me to try this? Try that?’”

Ultimately, Rocky’s voice is performed by puppeteer James Ortiz, but Streep’s cameo remains a hidden gem.

With Gosling anchoring the film as Dr. Ryland Grace, a schoolteacher turned astronaut who wakes up alone in space, Project Hail Mary opened March 20 to strong reviews and box office numbers.

And thanks to Streep’s surprise cameo, it carries a secret flourish that fans will be buzzing about long after the credits roll.