And that's before the murder at the elementary-school fundraiser.
"I thought that was a really unique opportunity to have so many incredible parts for women in one piece of material," said Witherspoon, who bought the rights to Australian author Liane Moriarty's best-selling novel and developed the project through her production company.
Witherspoon stars as high-strung Madeline. She's up in everybody's business, convinced she's always right. She's equally convinced that her ex-husband, Nathan (James Tupper), and his new wife, Bonnie (Zoe Kravitz), are always wrong, and she's not exactly the wife her adoring husband, Ed (Adam Scott), deserves.
Witherspoon said she wasn't sure she was up to playing that character. But scriptwriter David E. Kelley ("Boston Legal," "Ally McBeal"), director Jean-Marc Vallee ("Dallas Buyers Club," "Wild") and Kidman "were, like, 'What are you talking about? You're perfect for this character!' " said Witherspoon. "I don't know if I find that sort of offensive."
Yes, she could. Yes, she did. Without Witherspoon's performance, "Big Little Lies" wouldn't work.
It's not all about Madeline, however. Kidman stars as her friend Celeste, who seems to have a perfect, perfect husband, Perry (Alexander Skarsgård, "True Blood"), and perfect twin boys but she's hiding a dark secret.
As the series begins, something happens at the local elementary school. Somebody chokes Amabella (Ivy George), the daughter of Renata (Laura Dern), and fingers are pointed at the new kid Ziggy (Iain Armitage), the son of Jane (Shailene Woodley).
Battle lines are drawn, with Madeline leading the pro-Jane forces in a war against Renata. And there's a second front in this war: Madeline vs. Renata in a fight over whether the town should support a local production of "Avenue Q." Really.
In the words of the school principal, these are not helicopter parents they're "kamikaze parents."
This all plays out as a series of flashbacks, complete with other neighbors commenting on the principals, about a murder involving … well, somebody. Through six episodes, not only do we not know whodunit, we don't know who the victim is.
We're assured both questions will be answered in Episode 7, which was not screened for critics.
There's dark humor here, and some extremely dark drama including plotlines about an abusive husband and a woman dealing with a sexual assault years earlier. All this while the wives and mothers are dealing with 6-year-olds, teenagers, spouses, ex-spouses and more.
"I really related to all of the women in the book," Kidman said. "I mean, there's just such an array of emotions in this piece, and … we were excited to show the lives of these women in a very authentic way, and yet entertaining."
Witherspoon said when she read the novel, she saw herself "in different stages of motherhood all through my life. I was a mom when I was 22, like Jane; and then I was a mom who was 40, like Madeline. I've been divorced, I've been remarried.
"There were just so many aspects of it that were so relatable to the lives of women. It wasn't about them being good or bad. It's just that they showed every spectrum, every color of women's lives."
It's not just about women fighting with each other, it's about their "camaraderie," Kidman said. "There's pieces about women helping each other and supporting each other, which was very important to Reese and I."
To some degree, "Big Little Lies" is art imitating life. The two Oscar winners are "very, very close friends," Kidman said. "I love that it's about women coming together and making something happen very quickly with friendship being the core of it."
Witherspoon decried Hollywood's penchant for having "women of incredible talent" relegated to "thankless parts" as the wives and girlfriends of the male leads. She said that "for 25 years, I have been the only woman on set, so I had no other women to talk to. They call it like the Smurfette Syndrome where she's got 100 Smurfs around, but she's the only girl.
"But honestly, it's so refreshing to get to spend time with women."
She said she's "passionate" about developing and starring in projects that feature women in meaningful roles "because things have to change. We have to start seeing women as they really are on film. And not just in movie theaters on a tiny budget. We need to see real women's experience, whether it involves domestic violence, whether it involves sexual assault, whether it involves motherhood or romance or infidelity or divorce.
"We need to see these things because we as human beings need to learn from art. And what can you do if you never see it reflected?"
The seven-part limited series "Big Little Lies" premieres Sunday on HBO 7 p.m. on DirecTV and Dish; 10 p.m. on Comcast and continues on successive Sundays.