"My mum was like, 'Don't do that. Take some time off but don't give it up,"' Kidman recalled. "She said, 'Keep your toe in the water,' because, she said, 'You're going to want that as you get older.'"
Kidman now has four kids - two with husband Keith Urban, and two adult children with ex-husband Tom Cruise.
Earlier this year, the 50-year-old actress was nominated for an Oscar for her role alongside Dev Patel in Lion.
More recently, she received critical acclaim playing abused wife Celeste in HBO's hit series Big Little Lies with Reese Witherspoon and Alexander Skaarsgard.
Kidman will next appear in Coppola's new Civil War-era drama, The Beguiled.