Justin Bieber Schools David Letterman On Tweeting

Never Say Never star Justin Bieber swung by the Late Show yesterday, where he impressed David Letterman with his power to command throngs of screaming girls outside the Ed Sullivan Theater. The Bieb kindly taught Dave the ways of Twitter—or at least he tried—and when the late night talk show host asked the 16-year-old Grammy nominee whether he was a sophomore or junior in high school, JB simply deadpanned, “I don’t know—I’m Canadian.” Watch the mayhem—in 3-D, no less—below, Beliebers.