The biggest song of 2017 was written in just 90 minutes — which is enough to make any musician’s head explode with  wonder right about now.

Ed Sheeran’s “Shape of You” has since emerged as a modern day classic, breaking every chart and streaming record that stands in its way and offering up some of the catchiest lyrics pop music has ever heard. We can relate to the lyrics — “I’m in love with the shape of you.”

Co-writer Steve Mac has revealed the song was the first thing that sparked from a writing session with the pop star. An hour and a half later, they had a smash hit that was destined to go on and sell 3 million units.

“Ed is one of the best writers I’ve worked with,” Steve tells BBC’s Newsbeat. “He has a brilliant flow, the way he creates his rap and then adds a melody to it.”

After 27 years in the industry, Mac’s best advice is: “Even if the song doesn’t work that day, you may have found a new drum sound or a new melody to that song — never give up.”

Source: BBC Newsbeat