The 26-year-old singer said Bieber asked him to hit a golf ball out of his mouth during a trip to Japan – but Sheeran was “hammered” and hit his cheek instead.
“We were in Japan,” the Thinking Out Loud singer told the Guardian. “We’d been out to a dive bar. He just drank water and I got hammered. Then we went to a golf course, and he lay on the floor and put a golf ball in his mouth and told me to hit it out of his mouth.
“I was like, ‘F***, I need to aim this properly,’ and I swung. And you know in films when someone gets punched, and you hear that fake sound, like a slap?
“But in real life when someone gets punched, you hear that dull thud, a bit sickening? I heard a sound like the last one, and saw his security guard looking at me.
“I’d cracked Justin Bieber right in the cheek with a golf club. That was one of those ‘What the f***?’ moments.”
Sheeran's comments come hours after he tattooed radio presenter Roman Kemp with the wrong inking.
The singer – who is currently promoting his third album, Divide – was supposed to write "2017" on Kemp's leg but missed out the "1" and left him with "2007" instead.
The tattoo read: “Ed woz ere 2k7 x.”
Clearly unimpressed Kemp posted a picture of his new inking alongside the caption: “What the actual fuck has he done...”