Backstreet Boys are back, and we couldn't be happier. The group has been busy promoting their new single "Don't Go Breaking My Heart," and on Thursday night they gave a special performance of the song on The Tonight Show Starring Jimmy Fallon. After joining the host and The Roots for a special classroom instruments session of "I Want It That Way," the '90s boy band proceeded to make our hearts melt with their slick dance moves and swoon-worthy voices. Whether they're performing or adorably surprising fans in lifts, they still make us feel like lovestruck teenagers.