Nicole Kidman left her daughter "mortified" when she took her to school looking like a "wreck".

Nicole Kidman

Nicole Kidman

The 'Big Little Lies' actress - who has grown-up children Isabella and Connor with former spouse Tom Cruise and Sunday, nine, and Faith, seven, with husband Keith Urban - has been encouraged by her younger kids to always make an effort with her appearance because they get upset if she goes out looking too casual.

She told Tatler magazine: "You have an almost 10 year old and a seven year old - I mean, that's hard truth right there. They'll say, 'You're 50?'

"But it's interesting because particularly my little one will say, 'Please don't wear your work-out stuff to school this morning. Please blowdry your hair. Please wear some make-up.'

"I did show up one morning looking like a wreck I suppose... and my daughter was mortified."

The 50-year-old actress admitted she worries about getting older and tries to take care of herself because she wants to be around for her children.

She said: "I want to stay healthy and vibrant, I want to be able to take care of them... That's a big part of it when you have children when you're older."

Though playing a domestic violence victim in 'Big Little Lies' left Nicole feeling "very distressed" every day, she credits her children for helping her to shrug off the darkness of the role and come back down to normal life.

She said: "I have two little girls that are standing there while I'm thinking, 'Oh my God, I feel like I can't even go on.' And then they're asking, 'Errrr what's for breakfast?'

"That is a gift for me because that means you're thinking, 'OK, get it together'. Even just pretend you've got it together, but get it together."