Sheeran, 24, helped friend and fellow musician Jake Roche (of British pop band Rixton) pull off a picture-worthy proposal when Roche, 22, popped the question to girlfriend and Little Mix singer, Jesy Nelson, on Sunday.
"A year ago today I met her at Manchester Arena, so it was only right, with a little help from my friend, that this happened," Roche wrote along with an Instagram photo of himself on bended knee in front of Nelson. "Best day of my life."
Roche added that Sheeran, who was on a brief break from his X tour after performing three shows in London last week, had traveled 5 hours on his day off to help his friend propose. (Little Mix was performing as part of the Key 103 Summer Live event.)
Sheeran had taken to the stage as a surprise guest before Roche pulled off his proposal.
"Travelled 5 hours to sing our favourite song on his day off. I will never ever be able to repay you. Love you pal. @edsheeran," Roche wrote. Sheeran replied that it was an "absolute pleasure" and thanked him for "the KFC."
@Jake_Rixton my absolute pleasure. Thanks for the KFC— Ed Sheeran (@edsheeran) July 19, 2015
Nelson shared her own excitement on Little Mix's official Instagram:
"I cannot believe what has just happened! The most surreal moment of my life and everyone that I love most was there to share it with us! I feel like the luckiest girl in the world rite now literally cannot stop crying! Future Mrs Roche."
Nelson isn't the only Little Mix star who is engaged to a pop star – Perrie Edwards has been engaged to former One Direction singer Zayn Malik since 2013.