Reese Witherspoon became "deeply invested" in her 'Big Little Lies' co-stars.

Reese Witherspoon

Reese Witherspoon

The 40-year-old actress got really close to the likes of Nicole Kidman and Laura Dern on the set of the comedy-drama show and recalled how they would enjoy a glass of wine together after filming wrapped.

She said: "We talked about nothing to do with work. It was always just our personal lives: what's going on with our kids, single girls and who they're dating. We just became a really close-knit family, even with the kids, too - hanging out with them and playing with them.

"You get deeply invested in people. I think that's part of the experience of getting to know people. What deepens our relationships on set, even more than a rehearsal, is the glass of wine you have after work. 'What's on in your life? How's your mom? How's your heart?' That kind of stuff."

And Reese has an equally close friendship with her daughter Ava, 17.

She added to E! News: "People come up to her [all the time]. We were at a premiere and they were congratulating her on her performance. She's like, 'I'm not in the movie.' ... She is very supportive, and I love that she's here to help me.

Meanwhile, Reese - who also has 13-year-old son Deacon with her ex-husband Ryan Phillippe as well as Tennessee, four, with her spouse Jim Toth - previously admitted she often feels "guilty" when she is working away from her three children.

She said: "Every woman feels guilty if they're working or guilty if they're staying home all the time. There are all sorts of factors in between about economics and what each family needs. Actually my next show, 'Big Little Lies' has a lot to do with that and about the complexity of women's lives and the choices they have to make that affect their self-esteem and their marriage and their family ...

"You have to just live your life and make your own choices. Every family is different, and every family has to make their own choices, based on their circumstances. You have to rise above any negativity and know that you're doing the right thing for your family."