The video, which was posted on YouTube by Andy Richards on August 20, has already received more than 575,000 views.
During the three-minute clip, the guard twirls, walks slowly, bends his knees and even picks up something on the ground.
Clearly surprised by his actions, you can hear people discussing the guard's unusual actions on film.
Below the video, Richards writes: "Will Her Majesty be amused. A Buckingham Palace guardsman misbehaves on duty while The Queen is on holiday. His senior officer might be having a chat with him later…"
The UK's Mirror reported that the Ministry of Defence was investigating the matter.