Macklemore and Ed Sheeran drop surprise song 'Growing Up' about becoming a dad

Ben Haggerty's daughter Sloane was born two months ago

Fans can download 'Growing Up' for free from Macklemore's website

Ed Sheeran has revealed a new collaboration with rap duo Macklemore & Ryan Lewis, titled "Growing Up (Sloane's Song).

The 24-year-old chart-topper first teased the song earlier today, tweeting that it would be dropping at 5pm UK time, would be free and a new collaboration.

"You think you've guessed it but you haven't innit," he wrote, to 32,000 retweets from his millions of devoted followers.

Sheeran's vocals kick in for the chorus around the two-minute mark.

Fans can download "Growing Up" about Macklemore, real name Ben Haggerty's, emotional experience of becoming a father, for free from growingupsong.com.

Macklemore wrote on his website that the track is about "the joy and happiness that comes from bringing a baby into this universe", after telling the story of when he found out he was to become a dad.

"[Sloane] has filled my heart in ways that I never knew were possible," he gushed. "She is the love of my life. This song is for her."