Natalie Portman says her style has changed since becoming a mother.

The Oscar-wining actress welcomed son, Aleph, into the world last June and admits she has had to adapt the way she looks as she is keen to appear more mature.

''I've been trying to look more like a lady recently. I used to be happy in a T-shirt and sweatpants, and now I feel like I want to make myself a little more grown-up - now that I'm a mom.''

The 30-year-old beauty also says she loves vintage fashion because there's always a story behind the outfit.

Natalie - who is currently the face of Dior's Miss Cherie fragrance - told WWD: ''I feel like you are sort of stepping into history. It's really amazing to get the story of where a dress has been; you know that it has lived through many people's stories.''

It was recently revealed a lipstick chosen by Natalie for Dior will give its proceeds to the Free the Child Foundation.

The 'Black Swan' star is an ambassador for the charity, which helps liberate children from poverty, and chose it to receive money made from the sale of Rouge Dior's Nude Grege lipstick.

She revealed she picked the shade due to its number 169 having a special meaning to her.

She said: ''Six is the month that my whole family was born in - everyone was born in June. We're all June babies. Nine is a magic number, and one is my son - his name is one in Hebrew, Aleph.''