Tom Hanks is opening up about an important new co-worker.

During a post-screening Q&A for “A Man Called Otto”, the Oscar-winner spoke about working with his son Truman, who plays a younger version of him in the movie.

“Without a doubt, it’s special because, you know, I changed his diapers,” he shared, via People. “But you get past that right away because you gotta show up, and you gotta hit the marks, and you gotta do it on time, and you gotta be right there.”

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He praised his son as well for his professional attitude, and that they were both taking the role seriously.

“I know what that takes, and he does too. It’s a little different when it’s the whole shebang. He was cast for a very specific reason. We resemble each other, he’s not a stranger, and he knows what the pressure is, and he’s gotta do it,” he continued.

Hanks was also realistic about what entering a career as an actor meant, and had instilled this on his son.

“The thing that we both know is … you don’t know if you did a good job,” said the actor. “All you can do is wait for that very surrealistic moment when you see the movie, and it’s like, ‘There it is.’ It’s gonna last forever. Even then, I don’t think you have an idea of whether it works or not.”

As for Truman, he joked that part of his acting chops came from learning to imitate his famous father.

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“Whenever I do my imitation of him, people are like, ‘That’s not what he sounds like.’ But I have to convey to you the way I hear him. Everyone else hears, ‘Houston we have a problem’; I hear this grumpy old man who’s mad at the DVD player,” he said.

“A Man Called Otto” is based on Fredrik Backman’s 2012 novel A Man Called Ove. The film is set for release on Jan. 13.