Justin Bieber
The singer got emotional for his take on Fergie's 2006 hit "Big Girls Don't Cry."
Allison Brie
The actress emulated Jessie J, Ariana Grande and Nicki Minaj when she sang "Bang Bang."
Will Arnett
Inspired by his own film, The Lego Movie, Arnett performed "Everything Is Awesome."
Alison Brie
The Community actress slayed Salt-n-Pepa's classic "Shoop."
Will Arnett
"Who Let the Dogs Out?" Seriously, the Arrested Development star wants to know.
Marlon Wayans
The actor made the audience smile when he danced to Pharrell Williams' "Happy."
Queen Latifah
The talk show host got down to host LL Cool J's "Rock the Bells."
Salt
Kelly Clarkon's "Since U Been Gone" has never been so fierce!
Pepa
The rapper lit up like a firework when she covered "Firework" by Katy Perry.
Salt
Salt pulled out all the stops for her version of RUN-DMC's 1986 hit "Tricky."
Pepa
She's got a case of disco fever! Pepa performed Gloria Gaynor's 1978 anthem "I Will Survive."
Derek Hough
He raps? The Dancing With the Stars pro performed Macklemore & Ryan Lewis' "Can't Hold Us."
Julianne Hough
The Dancing WIth the Stars judge embarrassed her brother by performing The Lonely Island's "I Just Had Sex."
Derek Hough
The dancer recreated Sia's "Chandelier" music video.
Julianne Hough
The dancer brought out none other than Meghan Trainor herself when she mimed "All About That Bass."
Stephen Merchant
The actor covered "Hero" by Enrique Iglesias.
Malkin Akerman
"Pour Some Sugar on Me" by Def Leppard has never been so sexy!
Stephen Merchant
The Hello Ladies star got down and dirty to Christina Aguilera and Redman's 2002 club banger "Dirrty."
Malin Akerman
The Trophy Wife star knew every lyric in Jason Derulo's hit "Talk Dirty."
Hoda Kotb
The Today host shook her tailfeather during Sir Mix-a-Lot's "Baby Got Back."
Michael Strahan
The NFL Hall of Famer humped the floor while performing Fergie's "London Bridge."
Hoda Kotb
The Today co-anchor made Mark Ronson and Bruno Mars proud with her "Uptown Funk" performance.
Michael Strahan
The Live! With Kelly and Michael host crushed Bell BivDevoe's "Poison."
Mike Tyson
The heavyweight champ got people on their feet when he performed "(I Can't Get No) Satisfaction" by the Rolling Stones.