"Looking back on the highlights of my life, there's a moment I'll never forget from a day in London about two years ago," Swift wrote on Instagram. "I was in town to play the O2 and I was out shopping on my day off. My friend Ed Sheeran met up with me in this little shop where I was buying ballet shoes. He walks in and says 'you have to hear this new song. I think it's the best one I've ever written.'

"And then, as usual, he pulls out his phone and gives me headphones. I sat there on a bench in that store and heard 'Thinking Out Loud' for the first time, as little kids were picking out tutus and leotards next to us. Little did we know it would go on to be first dance song at countless weddings all over the world, become Ed's biggest hit, and eventually go on to win him Song of the Year at the 2016 Grammys.