Watch as Justin Bieber Forgets the Words While Dueting With Ariana Grande

Whoops! As if people needed more ammo with which to roast Justin Bieber. At Ariana Grande's show in Miami over the weekend, Bieber joined Grande on stage to sing The Weeknd's part in her hit "Love Me Harder," and he wasn't exactly well-versed in the lyrics. He actually fakes his part pretty well, and you have to pay attention to realize that over the screams, he's pretty unintelligible. What he lacks in accuracy, he makes up for in jumping around, and finally, around 2:20, he admits to Grande and the crowd, "I forgot the words." Watch to get ready for Monday night's big Bieber roast on Comedy Central.