Gwyneth Paltrow underwent a "massive software upgrade" when she turned 40.
The 43-year-old actress - who has children Apple, 11, and Moses, 10, with ex-husband Chris Martin - admits she has made a "bunch of changes" to her life since reaching the landmark age and is now more "content" and happy with herself than ever.
Gwyneth - who announced she had split from the Coldplay frontman in March 2014 but later admitted they had separated the previous year - said: "At 40, my life changed so much. I think every woman around that time gets this massive software upgrade. You're just different. You're upgraded.
"For me there were just a bunch of changes I had to make to really be true to myself and really live my happiness. And you have to be brave and make the choice to do that, to truly accept yourself and love yourself and really forgive yourself for your mis-steps.
"So it's been a long interesting road to get to the place where I feel really content and that I really know myself and like myself. I wish they could teach girls to do this when they are 16 instead of 40, but that's part of life."
The 'Iron Man' actress spent much of her marriage living in London and though she enjoys her life in Los Angeles, she does miss the UK city because it always made her feel more "awake and alive".
Asked if she misses London, she told Red magazine:
"Not in January, can I say that? My hardest time was always when you come back after the Christmas holiday until the February half term. You know what it's like!
"There are a few major things that I miss. I miss being an ex-pat, in that when you are in a city that is not the city you were born and raised in, you notice everything.
"I felt so awake and alive there and was in total marvel about the architecture and the history. As an American, you never get used to the beauty."
And Gwyneth loves being surrounded by the "sights and smells" of her childhood now she's back in California.
She said: "It's near enough to the ocean that you sometimes get that saline smell. I was born here and lived here until I was 11 years old, so these are all the sights and smells of my childhood: The bougainvillea, the ivy, blue skies, old telephone poles and the sea. Those are my sights and smells."