Ryan Gosling's children helped him with Project Hail Mary role

Ryan Gosling's daughters stepped in off-camera to voice his alien co-star in Project Hail Mary.

The sci-fi-adventure film sees science teacher Ryland Grace (Gosling) in space trying to save Earth from extinction, and he forms an unlikely connection with extraterrestrial Rocky.

And when his co-star was absent, Gosling, 45, enlisted Esmeralda, 11, and nine-year-old Amada - whom he has with his 51-year-old wife, former actress Eva Mendes - to voice the character so that the star could perfect his alter ego's reactions to the alien.

He told People: "Sometimes when I was working, and I needed to sort of switch things up or whatever, my kids would come in and I had an earpiece in my ear and they would talk for Rocky, so I could talk to them as Rocky.

"And there's some moments in the movie where I'm laughing, or I'm just so charmed by him, which is like, it's actually my kids talking to me and helping me out."

Esmeralda and Amada had to step in as Rocky - voiced by James Ortiz in Project Hail Mary - many times.

Gosling added: "They've seen many cuts of this film. They've given me many notes."

The star also revealed that one of his daughters influenced how Ryland should look.

He recalled: "When I was trying on stuff for the character, and my daughter came by, and she was like, 'You look smart in glasses.'

"And I was like, 'I need to look smart in this, so I will thank you for that.'"

It is not the first time Gosling has sought help from his daughters, as for 2023's Barbie, Esmeralda and Amada quizzed him on why he was playing the titular doll's long-term boyfriend, Ken.

In July 2023, Gosling told People: "My kids were my introduction to [Barbie]. I think they're confused as to why I would want to play Ken. They have no use for Ken."

And they helped him prepare for a heavier scene.

Gosling added: "My kids were around for the months at home, as I was prepping for it. So they, inadvertently, were prepping for it too.

"And they came to set that day, and were a huge sense of support, and doing it with me off-camera."