The American band OK Go is known for their creative, mind-blowing music videos, and their newest MV for "I Won't Let You Down" is no exception. You have probably already seen the incredible, large-scale umbrella synchronized dancing, but did you notice what's hiding in the video?

If you're paying attention at the beginning of the video, you can catch a cameo by popular J-pop girl group Perfume. 

The three beautiful members of the girl group appear as stage hands before the music starts. The girls' appearance is likely due to the fact that the music video's creative directors are Morihiro Harano and Kazuaki Seki, who have directed numerous Perfume videos in the past. The video was filmed in Japan in collaboration with Honda, who provided the UNI-Cub electric bicycles featured. The most impressive aspect of the video is that it was shot in one take. I can only imagine the amount of practice that must have gone into synchronizing that many people in evolving geometric formations!

What happens when six young strangers move into a mysterious boarding house? Watch Boarding House No. 24 to find out
And to get a taste of Perfume's unique style, here is one of their most popular music videos: