Katy Perry as a Cheeto.
Taylor Swift as a pegacorn.
Beyoncé as Rhythm Nation-era Janet Jackson.
Blue Ivy played the Michael to Beyonce's Janet.
Beyonce also dressed up as Frida Kahlo.
Kanye West may be too cool for Halloween but daughter North looked adorable as Pepe Le Pew.
Justin Bieber as a Power Ranger.
Lucy Hale as Twitter Dot Com.
Nicki Minaj as "the teacher's pet."
Fifth Harmony's Normani Hamilton as a mummy.
i got it from my mummy 💀
Fifth Harmony's Dinah Jane Hansen as an FBI agent.
RING THE ALARM 🚨 but I'll be damned if I see another chick on yo arm
Fifth Harmony's Camila Cabello as princess Jasmine.
Fifth Harmony's AllyBrooke Hernandez as an Egyptian princess.
Miranda Lambert as Rosie the Riveter.
Rita Ora as Barbie.
Aly & AJ as Romy and Michele.
Yes this happened last night......#postits #Romy&Michele
Ed Sheeran as Austin Powers.
Britney Spears as a witch.
Offstage she dressed up as sexy nerd.
Demi Lovato as a sugar skull.
Tinashe in a Mars Attacks mask.
Miley Cyrus as Dolly Parton.
Iggy Azalea as a character from the movie White Chicks.
Jennifer Lopez as the devil.
Ariana Grande as a vampire.
me n suz
Rihanna as a Teenage Mutant Ninja Turtle.
Teenage. Mutant. Nigga. Turtle$