Jason Derulo and Luke Bryan Karaoke

There is an app called Sing! It allows two people in different places duet on a song together.

Obviously, this is way cooler when two famous people do it!

For instance, Luke Bryan just posted a video on his Facebook of him and Jason Derulo singing Jason's hit, "Want To Want Me."

Who knew Luke Bryan had such a falsetto?

Jason has collaborated with Luke before at last year's CMT Awards. They did a mash up of "Talk Dirty" and "This Is How We Roll."