Actor Lucas Hedges had to plead with his director dad not to use his childhood nickname on the set of their new movie Ben Is Back to avoid embarrassment.

The Manchester by the Sea star reunited with his father, filmmaker Peter Hedges, for the new family drama, in which Lucas portrays a recovering drug addict, but the Oscar nominee had to pull his dad to one side and request more professional boundaries after cringing at a lovable term he used onset.

"I called him Pete (during production)," Lucas told breakfast show Good Morning America. "I got to set on the first day and he called me 'Bubba' in front of the whole crew, which is what he calls me (at home), and I was just like, 'Dad, you can't do that!'

"It was just like, 'No, that's not gonna work.'"

The project marks the second movie Peter and Lucas have worked on together, following 2007 dramatic comedy Dan In Real Life, and although that experience initially turned the young star off the idea of being directed by his dad again, he knew Ben Is Back would be something different - especially when Julia Roberts requested he play her onscreen son.

"I read the script and fell in love with the script, and was like, 'Wow, OK, this could be really special,'" Lucas recalled, "but her (Julia)... really wanting me to do that (play her son) sort of tipped me over the edge. It was very flattering."

The film's tough subject matter also hit close to home for the Hedges, as substance abuse has affected the lives of so many around their circle of family and friends, and their personal ties to addiction gave Lucas, who turns 22 next week (12Dec18), something to draw from for his performance.

"Some of my best friends are in and out of halfway houses," the actor shared, "so it feels like a story that I was able to witness from a very close vantage point in the sense that I saw them from a young age and then saw them struggle with what addiction did to them... It's different in everyone's case, but it seems to sort of eat away in a similar fashion."

Ben Is Back is one of two emotionally-charged dramas Lucas is currently gaining critical acclaim for - he also stars in Joel Edgerton and Nicole Kidman's Boy Erased, about a homosexual kid forced to undergo church-supported gay conversion therapy.