It happens on America's Got Talent, where the judges disguise as "Wax Figures" and Mel B quick tickle a fan with a feather. Not laughing reaction but it's funny.
https://www.youtube.com/ watch?v=f8ATHGEEuWI
It happens at 2:30.
https://www.youtube.com/ watch?v=f8ATHGEEuWI
It happens at 2:30.