Gwyneth Paltrow knew on her 38th birthday that her marriage was over.

Although the actress was 41 by the time she and Chris Martin announced their split in 2014, Gwyneth admitted that, in her mind, the marriage was over long before then.

In a new personal essay in British Vogue, Gwyneth said: ''It was my birthday, my 38th. My ex-husband and I were tucked away in the Tuscan countryside, on a hill in a beautiful cottage with a view of the forest. Fall was coming; the leaves were just loosening their grip on bright green. Inside, the cottage was perfectly appointed in the way you dream of for a birthday trip: cosy living room with a fireplace, kitchen table overflowing with spoils from the farm nearby - peaches, tomatoes on the vine, basil, eggs. I don't recall when it happened, exactly. I don't remember which day of the weekend it was or the time of day. But I knew - despite long walks and longer lie-ins, big glasses of Barolo and hands held - my marriage was over.''

Gwyneth, 47, revealed she tried to silence her doubts but they never completely went away.

She wrote: ''I tried to convince myself it had been a fleeting thought, that marriage is complicated and ebbed and flowed. But I knew it. It was in my bones.

''At first, I was moderately successful at turning the volume down on that knowledge. It would be years until we said the words aloud. But, that weekend, a dam had cracked just enough to hear the unrelenting trickle of truth. And it grew louder until it was all I could hear.''

And Gwyneth - who has children Apple, 16, and Moses, 14, with her ex-husband - revealed she and Chris, 43, actually split up about a year before they announced to the world via her goop newsletter, that they had ''consciously uncoupled''.

She said: ''When we made a commitment to approach our separation this way, and about a year before we introduced the phrase to the world, we put it to the test. It was hit and miss. We had great days and terrible days. Days when we couldn't stand each other, but forced ourselves to remember what we were aiming for. I worried about the world finding out that we were no longer together before we were ready to say it. And how to say it? What to say?''

Gwyneth tied the knot with second husband Brad Falchuk in 2018 but revealed she will always have a special place in her heart for Chris, who she divorced in 2016.

She said: ''I know my ex-husband was meant to be the father of my children, and I know my current husband is meant to be the person I grow very old with. Conscious uncoupling lets us recognise those two different loves can coexist and nourish each other.''

Read the full feature in the September issue of British Vogue available via digital download and on newsstands Friday 7th August or go to https://www.vogue.co.uk/arts-and-lifestyle/article/gwyneth-paltrow-conscious-uncoupling