When Justin Bieber's 'Boyfriend' video dropped, filled with rooftop dancing and fast cars, he claimed to have no prior knowledge of 'N Sync's vid for 'Girlfriend,' which was similarly named and themed.

Well, someone who goes by the Raheemdaplaya04 handle has buckets of creativity and a whole lot of time on their hands, not to mention the digital equipment and the wherewithal, since they created a mashup of both songs and videos. The end result is seamless and flawless, proving that the videos and the songs are closely related.

If any mashup video deserves to be in the mashup hall of fame, it's this perfectly executed piece of work. If such a body does not exist, this video is reason enough to create one, since it shows how explosive the combo of creativity and equipment can be. It sounds like one song and looks like one video. That's certainly not easy to do.

There's lot of dancing and lots of shots of the Justins – both The Biebs and Timberlake, who has seemingly left music behind for movies. Still, footage of him singing and dancing reminds us of his boy band glory days. It's a nice walk -- er, ride, since these vids have lots of fast cars -- down memory lane.

This mashup proves that the song and the video are more similar than you might think. There doesn't appear to be any gaps... at all.

Watch the Justin Bieber 'Boyfriend' + 'N Sync 'Girlfriend' Mashup