The Mad Men star - who is a natural blonde - changed her hair colour when she was modelling early in her career, and despite initial criticism, she decided to keep her flame-coloured look after beating off competition from a number of other models thanks to her new bright tresses.
She said: 'When I first started modelling I was blonde. Then I got a job and they wanted to do my hair bright red. I'd always wanted to, but the head of my agency was like, "You look terrible, it's so ugly, you cannot have red hair."
'I came back as a redhead and couldn't get my hair back to blonde for two days - in the meantime I had to audition.
'I booked two or three jobs, because were a lot fewer redheads than blondes, and I was like, this is working for me, I'm keeping this!'
Christian also credits her flame-coloured locks for helping her to land Hollywood movie roles, such as 2011 action film Drive, and she says her hair ensures people remember her.
She said: 'I think it does make you stand out. People remember you when there's a sea of faces. It helps.'
Blondes don't always have more fun: The actress in a 1997 TV commercial