Sienna Miller has an "intense relationship" with her daughter

In an interview with PEOPLE Now, she said: "My daughter challenges me and is a real mirror. When you have a child and you're raising a child you see aspects of your character in that person reflected back, it's the most loving, intense relationship that I have. There's nowhere to hide, she knows me I know her and that's a beautiful thing. She's really stubborn which is very like me, I see her as her own person but I see genetic things in her. She's heaven my kid."

Sienna plays Debra Callahan in new Jake Scott-directed drama 'American Woman', a single parent who is left to raise her grandson after her teenage daughter disappears without explanation.

The British star admits it was "hard" shooting the project because she had to do a lot of travelling and spend a lot of nights "alone".

She said: "The getting home at night was heavy, my daughter was with me for a lot of it but there were times she was in school, she was travelling back and forth, there were a lot of nights alone and it was hard. It was a hard game."

The 'American Sniper' star also went on to reveal that her character in the much-anticipated film reminds her a lot of her own sister, fashion designer Savannah Miller.

She said: "My sister, so similar to Deb in this. I think it exists in humans and that's what beautiful about this movie is that there is this resilience of the human spirit that no matter what happens this woman gets back up.

"She has a safety net and a wonderful relationship with her family and I know a lot of women who would be the same that no matter what happens they get back up and that's a wonderful thing to explore."