Imagine this: You're a tourist, visiting the Top of the Rock in NYC, and you are asked to take a photo against the beautiful city view. Now, what would happen if you were to get photobombed by, say, Mad Men hunk Jon Hamm and The Tonight Show host Jimmy Fallon? Well, Jon and Jimmy decided to find out when Jon took part in Jimmy's new skit "Celebrity Photobomb" and pranked several families. Watch the video above to see Jimmy and Jon's surprisingly good photobombing skills and what happens when a group of ladies see Jimmy sneaking around behind them.