The 32-year-old star admitted that maintaining her locks take a lot of work, but it's worth it because the children at her six-year-old daughter Harlow's school love the radical new hairdo and think it makes her look like a character from Disney's 'Frozen'.
Talking at the Lucky Fashion and Beauty Blog conference in Los Angeles, she said: "I coloured my hair for my daughter. It's a lot of upkeep actually, but I'm very popular at her school. Everyone talks to me when I pick her up because they think I'm a character in 'Frozen'. It's great!"
Nicole cites her mother as her style inspiration and claims she often borrowed her clothes. Brenda Harvey helped raise Nicole with Lionel Richie after her biological parents, Peter Escovedo and Karen, decided they couldn't financially provide for her.
According to E! Online, Nicole - who also has four-year-old son Sparrow with her husband Joel Madden - added: "My mum was my style inspiration growing up. In my mind, she was a princess ... She was doing her thing in the '80s with her Alaia skirts and Chanel bags. The majority of my vintage is from her ... I just stole it all.
"We're all going to look back and laugh at how we dressed today. Fashion evolves and it changes, you just have to have a sense of humour about it."