Ed Sheeran needed hospital treatment after Princess Beatrice sliced open his face with a ceremonial sword during a botched prank.
He was taken to hospital after the exclusive Windsor Royal Lodge party and later showed off the cheek wound, which required stitches.
The accident happened after ex-soldier Mr Blunt joked that he would love to become a Sir.
A source told the paper: "The blade cut into his face and it was just a few inches from his right eye.
"A couple of the guests said it could have been worse and he could have been blinded in the eye, but Ed really played it down."
Princess Beatrice was said to be "very upset" by the incident but the singer tried to reassure her.
The paper claimed Mr Sheeran, who was with girlfriend Cherry Seaborn, was able to return to the party after his hospital visit.
