A  mutual friend introduced Reese Witherspoon and Laura Dern in front of a restaurant in the Brentwood Country Mart complex in Santa Monica, California. They were already aware of each other; it was 2011, and both were movie stars of many years. They had also each played anti-heroines in back-to-back late-1990s Alexander Payne films to unforgettable effect: Dern as Ruth Stoops in Citizen Ruth and Witherspoon as Tracy Flick in Election. But it was merely a quick hello.

They reunited in 2014 to play mother and daughter in Wild, a film based on Cheryl Strayed’s memoir that garnered them both Oscar nominations. A friendship blossomed quickly — playing family, as luck would have it, made them so. They now star (and spar) as rival Monterey, California, power mothers in the new HBO miniseries Big Little Lies, of which Witherspoon is also an executive producer.

Speaking by telephone and email, Witherspoon and Dern talked about their fast-tracked friendship, multiple collaborations and conversations with their mothers (Dern’s is actress Diane Ladd). Some excerpts:

Reese Witherspoon (RW): I was with Howell outside a restaurant. Howell Caldwell’s our friend who’s a first assistant director, who’d worked with Laura, and he’s this big, funny guy from Texas, and he’s like: ‘You gotta meet Laura Dern. You’re gonna love her, you’re gonna love her mom.’ Her mom is, like, the quintessential Southern mom, and I have a real Southern mother, too. He said, ‘You guys are gonna be best friends.’  And I remember thinking: ‘Could I be best friends with her? I don’t know.’

Laura Dern (LD): We’d both worked with Alexander Payne and I felt this real kinship and connection through that, and pined to know her because of Southern family and Southern mothers.

RW: I see a lot of similarity in the way that you and I work, with humour, but also this understanding of conscious people acting unconsciously. The reason I did Election was because of Citizen Ruth.

LD: There couldn’t be two more hateful characters in Alexander’s movies than ours. It was really fun to be silently bonded by having to play these sort of awful people in the most delicious way.

RW: On Wild, we didn’t get any rehearsal time. We immediately started, Day 1, with an incredibly emotional scene, and we just started laughing because it was so absurd to meet in this —

LD: Was it in the car?

RW: No, you were in the bed in the hospital dying.

LD: Right! I was lying there trying to be dead, and she was so pure and so raw and exposed that I was trying not to weep, and then I started to laugh.

RW: Nobody makes me laugh harder than Laura. She can put me on the floor with a text message.

LD: We were also in this story of grief and true love and the mother-daughter relationship, which Reese and I both have with our mothers and all of that invited our friendship instantly. We just dove in. Reese was working every second. I’d come to set and want to say ‘Hi’ and they’d say, ‘Well, she’s hanging off the side of a cliff right now.’

RW: The day you had to come and I was doing a sex scene in an alley? All the sexuality was tied in with my (character’s) mother’s death, so there were all these times when Laura had to witness me having sex with men in an alley, or in a hospital bathroom. On the press tour (in Portland, Oregon), we ate a ton of food at Tasty n Alder and, after a few glasses of wine, ran around Powell’s Books creating an impromptu travelling book club. Then we went to Voodoo Doughnut and ate Wild-themed doughnuts the owners created for our premiere. We were together all over the world for five months. She taught me to love Red Vines. She taught me about brown lipstick.

LD: You know someone is your favourite person when you’ve done a day of press, listened to yourself ad nauseam, listened to them tell every story, and when it ends, it’s like, ‘Are we going to eat something?’

RW: ‘What are we doing now?’

LD: ‘Why don’t we drive there together?’

RW: ‘Why don’t we just share one room?’

LD: And after playing out, you know, a true love story between this mother and daughter, to hate each other (in Big Little Lies) is just hysterical.

RW: My mother called me the other day — Laura, I didn’t tell you this — (she) was like: ‘I don’t like that show. I just don’t like it.’ She’s like: ‘You’re too mean. It just bothers me how mean you are.’

LD: My mother called me — and she’s an actress — and goes, ‘You didn’t prepare me for what a bitch you are.’ I’m like, ‘I didn’t know I was supposed to prepare you for any character I play!’ And she said, ‘Yeah, but you’re a bitch to Reese.’

RW: Your next article should be about how our mothers met. They watched Wild together in a theatre holding hands.

LD: We love each other’s families. I was just in London and my son sprained his ankle and Reese texted me: Did I need anything? Or, when Reese was away, I got to have dinner with her daughter.

RW: On Mother’s Day we were with our mothers and our kids, and her mother was telling us stories about old Hollywood. Our daughters go out to lunch and dinner and talk, even though they’re just teenagers. It’s nice for them to have a place to talk about their shared experiences as children of actors, children in show business.

LD: When I met Reese, I knew she would be my family for the rest of my life. And I don’t say that lightly.

RW: Now every time Laura’s on a movie that I’m not in, I’m jealous. I’m having FOMO (fear of missing out). How dare she do Star Wars without me?

LD: I get so upset. My daughter said to me the other day, ‘I saw the funniest picture of Reese with Mindy Kaling, it was so cute.’ I was like (sobbing sound). It’s like middle school.

RW: She’s going to piss me off at some point, though.

LD: And when I do, I expect that we’ll go to therapy for it.

RW: And by therapy you mean a bar, right?

LD: Exactly.