This guy would make Mr. Bean proud.
Identified only as "Yankel," the tourist succeeded in getting a member of the Queen's Guard -- famous for their ability to keep a straight face -- to crack a smile while he stood watch outside one of London's royal residences.
A YouTube video of the encounter opens with Yankel approaching the guard somewhat hesitantly. "Go right up to him," a voice says behind the camera, encouraging him to pose with the man. "You just can't touch him."
"We're in this thing together, right?" Yankel says to the motionless, expressionless soldier, striking a pose and smiling comically.
From there, the tourist launches into some improv comedy, based on the premise that he and the guard are actually old friends who went to school together. After nearly a minute of good-natured ribbing, the soldier stifles a giggle and cracks a smile, shaking his head at himself as he does so.
The Telegraph reports the guard is wearing the uniform of the Household Cavalry Regiment.
WATCH the Queen's Guard crack a smile, above.