Christina Hendricks begged 'Mad Men' bosses to let her wear her hair down.

The 39-year-old actress is known for playing secretary-turned-advertising firm partner Joan Holloway on the hit show but admits she was never keen on her character's trademark up-dos.

She said: ''One thing I tried for years and was told no every time was I wanted her to have her hair down. And my boss said, 'Women find a style they like and they stick to it', and I went, 'That's the craziest thing, my girlfriends and I are changing our colours and cuts all the time.''

However, the newly-blonde beauty came around to the idea of her having a signature look after a while but claims it could take the hair department up to three hours to perfect Joan's hairstyles.

She told People magazine: ''Now I'm glad, because it ended up being her look. I think I've had every possible updo known to man over the past seven years.

''In the beginning it was very tight and very sprayed, and by the sixth season I was like, 'Come on' she's going to a party. Can't we just loosen it? How about a little more Brigitte Bardot?' But there was very little wiggle room - they watched my hair like a hawk. I heard there was a threat at one point that if I kept asking to put my hair down, they were just going to chop it off.''

Christina also confessed starring on the show has massively improved her own personal sense of style.

She added: ''I think I dressed very differently before 'Mad Men', because I didn't know better. You learn as you go. I learned so many things from Janie Bryant, our costume designer, about tailoring, about fit and the things that really suit you.

''I would run around with flowers all over me if I could, and then I realise that it's not particularly flattering. I've learned to take the things that I love from all those elements and take it back into the shapes and silhouettes that work so well for me on the show, and sort of blend the two in my real life. You have to sort of learn as you go.''