Last night, Echosmith performed their smash hit, "Cool Kids," on the season finale of American Idol. They were joined by finalist Joey Cook. Check out a video of the performance below and leave us a comment with your thoughts!

Video: Watch the Muppets perform Echosmith’s “Cool Kids”

Echosmith will play the Rock In Rio Festival in Las Vegas this Friday, alongside Taylor Swift, Ed Sheeran, and more. Further information can be found over at the band's official website.