Eva Longoria says her ''best beauty secret'' is hair dye.

The 'Desperate Housewives' star - who appears in L'Oreal's new at-home hair colour campaign - loves doing her hair from the comfort of her own time as she enjoys having some ''me time'' when she does it.

She said: ''I always say, every time I'm on a red carpet, [my look] is an illusion. Those aren't my lashes and that isn't my hair colour, or my cleavage! I've always been open and accessible to people about my journey on many things. And there's nothing scary about having grey hair, especially because you can fix it. Home hair colour is the best beauty secret that people often look over. But there is so much amazing technology now in at-home hair colour, and it's so easy, that you don't need to spend money on going to the salon.

''It's my me time, when I colour my hair. It's like a sacred moment between me and my greys. I say, goodbye, and 'thank you very much for the wisdom that it represents.' It's so fun, colouring at home. Just the satisfaction you get when you take that towel off and blow dry your hair. You just feel like a new person. It can transform us.''

And Eva admits she didn't ''understand'' it when she found her first grey hair when she was 16-years-old.

She added to People magazine: ''I remember, when I my first grey, I didn't understand it and I thought, 'Whatever.' It wasn't until college where I was like, 'Oh my gosh, there's more.' Then, I moved to Hollywood where I was like, 'They can't know I have grey hair. I'm only 22. I have to cover these!' ... When I was young, I coloured my mother's hair with a box colour, and then once I needed to cover my greys, I used box colour.''