Lucas Hedges made it ''pretty clear'' he didn't want to make a movie with his father before he signed up for 'Ben Is Back'.

The 22-year-old actor was his co-star Julia Roberts' first choice to play her drug-addicted son in the movie, but filmmaker Peter Hedges warned her it was highly unlikely the 'Manchester By the Sea' star would agree to take the role.

Peter said: ''He'd been pretty clear he didn't want to do a film with me. And while I didn't necessarily like that that was the case, I respected it and I was never going to ask him to be in it.''

Lucas admitted he wanted to forge his own career and also worried it would be ''gross'' having to discuss a character intimately with his father.

He said: ''[It's] so gross! A somewhat graphic, overly detail-oriented conversation about something that is my private life? The only other thing like that is sex.''

But the actor eventually relented and spent some time living with Julia, her husband Daniel Moder and their three children in California.

She explained in an interview with the Guardian newspaper: ''I thought I needed to bridge the gap between the family that I have and am devoted to, and the family that I'm about to join.

''You really want to know who you're getting into the dark of night with. And I think that we were all pretty clear on who we all were by the time we got to New York.''

And once shooting began, Lucas and Peter rarely spoke off set to the point that spending Christmas together with the rest of their family was ''bizarre''.

Lucas laughed: ''It was so bizarre. Christmas morning with my director? I have to get him presents? He's giving me presents? So weird!''