The Oscar winner plays an FBI investigator dealing with the brutal murder of her daughter in the Billy Ray film and she admits she'd have struggled with her grief-stricken character had it not been for the fact her supportive husband Danny Moder was the project's cinematographer.

She also credits the perfect casting of newcomer Graham, who follows up Boyhood with the new drama.

"As soon as Zoe Graham, who plays my daughter, got cast we went for breakfast and you fall immediately in love with her," Roberts tells WENN. "She's so bright and articulate and her interests are so diverse and bohemian and she's in college studying textiles. She's the person I want to be when I grow up!

"It made me so absolutely connected to the idea of Jess (character) having lost her husband and raising this child by herself and watching her grow up into this magnificent human being that she gets to admire and feel responsible for; and everything is about getting back to the kitchen to talk to her.

"That relationship is so touching to me and Zoe did such an impeccable job. Everything made sense about how in love this woman is with her daughter."

And as Roberts dealt with her movie daughter's death and ageing 13 years over the course of the film, she turned to Moder for help and encouragement.

"He's my favourite person on the planet so I love spending time with him and I love his work ethic and his point of view," she coos. "When you do have scenes where you're really exposing yourself in a way that I wouldn't do... if he was sitting right behind me and I felt some sense of security it makes you want to do more.

"The biggest preparation for me was what she (character) looked like in the beginning and what she looked like 13 years later and then constructing the performance around that," Roberts adds. "I figured it out with my husband. You don't want it to look too contrived or too created. We tested a few different things and tried to make it seem real 13 years later; more damaged."