Confronting Streep with her own parental weakness and revealing the damage she did to her son Perry (Alexander Skasgard), when she blamed him for the death of his brother Raymond, set up a powerful exchange between the two women, both still mourning his death.
Kidman said: "There's such complexity to what she's been through, how she's coping and then still trying to navigate the future for herself as a single mother with two kids. That to me was a really strong arc."
The Aussie superstar has teased season three may be on the cards if the ensemble, which includes Reese Witherspoon, Laura Dern, Shailene Woodley and Zoe Kravitz, were able to find time in their busy filming schedules.
Fans were already calling for more, after the final scene saw the so-called Monterey Five walk themselves into the local police station to apparently admit their roles in Perry's death.
Kidman said she relished the opportunity to try her hand at an extended TV role, the first in the 52-year-old's career.
"To play that character through 14 episodes, and to be doing something for the first time in my career, this is a first for me," she said.
She tackled the role of the abused wife and struggling mother with full force, working with a professor of psychology to get to the truth of how domestic violence sufferers respond.
"Celeste had this depth and this intelligence, yet you know she's in a coping mode right now and she's sabotaging herself at times and doing things because she's grieving. She's also in a position where she's carrying a massive secret [over her husband's death], so she's been unable to really heal because of all these things. So that's the drama of it and in terms of that conflict, I found that really hard. Because it wasn't a matter of going, 'okay, this is a woman who's gone through trauma and is now ready to take on the world.' You're watching her unravel," Kidman explained.
"But also, she is a really good mother. Does she have problems? Yes, but the children know how to deal with their mother and they're a family. These boys have lost their father so the idea of them losing their mother is traumatising. I think that's something all of us in this culture know about the power of motherhood, but then how do you get her to a place to help her which I think is also important," she pondered.
Big Little Lies is streaming on Neon and screening on SoHo2.