Emma Thompson has shared the heartbreaking truth behind 'Love Actually's' most emotional scene.

The moment in question sees Thompson's character Karen, after learning her husband has bought jewellery for another woman, crying secretly in their bedroom in an attempt to hide her tears from their children.

The Telegraph reports that Thompson reflected upon the scene from the 2003 Richard Curtis film at a fundraiser for the Tricycle Theatre in London on Sunday (25 February) revealing she drew upon the heartbreak she experienced following her past relationship with Kenneth Branagh.

“That scene where my character is standing by the bed crying is so well known because it’s something everyone’s been through,” she said, adding: “I had my heart very badly broken by Ken. So I knew what it was like to find the necklace that wasn’t meant for me. Well, it wasn’t exactly that, but we’ve all been through it.”

Thompson met Branagh married in 1989 after meeting on BBC drama 'Fortunes of War' two years previous. They went on to work together on several more projects, including 'Peter's Friends' and 'Much Ado About Nothing'.

The couple's marriage would break down in 1994 after Branagh had an affair with his 'Mary Shelley's Frankenstein' co-star Helena Bonham Carter in 1994.

Speaking to The Sunday Times years later, Thompson revealed she had no hard feelings for Bonham Carter, saying: “That is... all blood under the bridge. You can’t hold on to anything like that. It’s pointless. I haven’t got the energy for it... Helena and I made our peace years and years ago... she’s a wonderful woman.”