Sitting two rows behind the trio who were have their photo taken, the young royal gave a double thumbs up as he leant between other spectator’s heads to appear in the shot.
And last week the Queen photobombed two members of the Australian hockey team as they posed for a selfie.
“Aaaahhh the Queen photo-bombed our selfie,” hockey player Jayde Taylor, who was posing with team-mate Brooke Peris, wrote as she posted the image on Instagram, to hundreds of likes.
Prince William’s photobombing came as he visited the athlete’s village in Glasgow with the Duchess of Cambridge and Prince Harry and met Sir Chris, the country’s most successful Olympian, and Jamaican sprinting star Usain Bolt.
Sir Chris declared himself chieftain of the village.
Before the royal visit he tweeted: “Nice 2get the kilt out again 2day for my role as VillageChieftain. Some exciting guests to host incl the Cambridges, PrinceHarry & UsainBolt”
Prince Harry’s unexpected guest appearance in the photo at the Tollcross International Swimming Centre so pleased former Olympic boxer Trevor Shailer, seen on the right next to rugby sevens coach Sir Gordon Tietjens, 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 hockey players who were “photo-bombed” by his grandmother last week.