The fourth-in-line to the throne gave a cheeky thumbs-up and a wide grin when he popped up at the back of a group shot with New Zealand team officials at the Tollcross International Swimming Centre yesterday.
Former Olympic boxer Trevor Shailer, seen on the right next to rugby sevens coach Sir Gordon Tietjens, was so pleased with the unexpected guest appearance that he posted the picture on his Facebook page.
He wrote: "Photo of the day... A Royal photo bomb by Prince Harry with Titch (Sir Gordon) and Gary Hermansson at the Swimming venue tonight.
"Thanks to Bev Hari for taking the pic... fun times supporting our athletes at the Glasgow Commonwealth Games!!"
The picture was taken just hours after Prince Harry met two Australian players who were "photo-bombed" by his grandmother last week.
Jayde Taylor was posing for a photo with team-mate Brooke Peris when the Queen appeared in the background smiling over her shoulder.
The hockey player then posted the picture on Twitter, where it was retweeted thousands of times with the hashtag #queenselfie.