Katy Perry and Madonna

Katy Perry and Madonna both opted for Moschino gowns.
Katy Perry and Madonna both opted for Moschino gowns.
Kate Hudson in a Michael Kors gown.
Jennifer Lopez in custom Versace.
The designer behind Selena Gomez's white-hot gown opted for a deep-v black number for herself.
The actress was statuesque in white Atelier Versace, Alexandre Birman shoes and Anna Hu earrings.
Sofia Vergara rocked her signature sweetheart neckline in a blush-hued Marchesa dress.
The model wowed in an ethereal Versace gown.
Olivia Munn in a pleated, ombre J. Mendel dress.
The 18-year-old in steel blue Calvin Klein.
Kristen Wiig was angelic in soft yellow Prabal Gurung.
The pair (well, Kim mostly) stole the show in Roberto Cavalli.
The model was regal in Dolce & Gabbana.
Anna Wintour in Chanel Couture at the Metropolitan Museum of Art's Costume Institute benefit gala, celebrating "China: Through the Looking Glass," in New York on May 4.
The supermodel in a red satin mini dress by Tommy Hilfiger.
Gong Li at the Metropolitan Museum of Art's Costume Institute benefit gala, celebrating "China: Through the Looking Glass," in New York on May 4.
John Boyega in Burberry at the Metropolitan Museum of Art's Costume Institute benefit gala, celebrating "China: Through the Looking Glass," in New York on May 4.
Marissa Mayer in Oscar de la Renta at the Metropolitan Museum of Art's Costume Institute benefit gala, celebrating "China: Through the Looking Glass," in New York on May 4.
Wendi Deng Murdoch in Oscar de la Renta at the Metropolitan Museum of Art's Costume Institute benefit gala, celebrating "China: Through the Looking Glass," in New York on May 4.
Anna Wintour wears Chanel while walking the carpet with daughter Bee Shaffer, who wore Alexander McQueen.
A dapper Ansel Elgort in Tom Ford.
SJP turned heads in a custom Philip Treacy headpiece and a satin dress she co-designed with H&M.
The duo looked sharp in Ermengildo Zegna.
Joshua Jackson and Diane Kruger (in Chanel) arrived for fashion’s biggest night at the Metropolitan Museum of Art in New York on Monday.
Larry David arrived for fashion’s biggest night at the Metropolitan Museum of Art in New York on Monday.
Kenneth Cole arrived for fashion’s biggest night at the Metropolitan Museum of Art in New York on Monday.
Keri Russell in custom Altuzarra.
Poppy Delevigne in a floral-inspired Marchesa gown.
Dwyane Wade in Versace.
Gabrielle Union carried a Charlotte Olympia clutch as she arrived for fashion’s biggest night at the Metropolitan Museum of Art in New York on Monday.
Jennifer Lawrence arrived in Dior for fashion’s biggest night at the Metropolitan Museum of Art in New York on Monday in a beaded floral Dior gown.
The designer, in a Brooks Brothers tuxedo, arrived with Katie Holmes, who rocked a Zac Posen dress and short new bob.
Alicia Keys in a Jean Paul Gaultier ensemble.
The Girls actress in Giambattista Valli Haute Couture.
Amanda Seyfried in an embellished Givenchy gown.
Anne Hathway arrived for fashion’s biggest night wearing a hooded, gold Ralph Lauren number.
The actress in Dolce & Gabbana.
The Glee actress in Tory Burch at the Met Gala.
Emma Roberts in emerald green Ralph Lauren.
The model in a lavender Gucci number.
The model stunned in a purple embroidered Versace gown.
Ivanka Trump in a custom strapless Prabal Gurung gown.
Community co-stars Joel McHale and Alison Brie (in Prabal Gurung dress and Louboutin shoes) hit the red carpet together.
Maggie Q (in Tory Burch) and Dylan McDermott stepped out together on Monday evening.
Josephine de la Baume (in custom TopShop) attended Monday's Gala with husband Mark Ronson.
The pop star wowed in a white Vera Wang gown.
Like SJP, Vanessa Hudgens also opted for an H&M dress for Monday's Met Gala.
Actress Tang Wei in a Burberry gown.
The actress rocked a knee-length Coach dress and Repossi earcuff.
Claire Danes in a bold berry lip and Valentino gown.
Courtney Eaton in a Dolce & Gabbana frock and headpiece.
Elizabeth Banks in a blue Michael Kors gown.
The model-turned-actress in a TopShop dress.
Hailee Steinfeld in a blood-red Michael Kors satin gown.
The singer rocked a dramatic black cape and dress she co-designed with H&M and Nicholas Kirkwood heels.
Jessica Chastain was glowing in a gold Givenchy gown.
The Academy Award winner stunned in black Givenchy.
Kate Mara took the plunge in a custom white gown by Diane von Furstenberg.
The Scandal actress upped the drama in a full gown by Prada and Harry Winston jewels.
Kris Jenner in a bright red Balmain dress.
The model was elegant in a Carolina Herrera gown and fun, fish-shaped Judith Lieber Couture clutch.
Lily Collins rocked Chanel Couture on the red carpet.
Lizzy Caplan wowed in Donna Karen Atelier.
The twins both rocked vintage Christian Dior on Monday evening.
The recently married couple was glowing at Monday's gala.
Rachel Weisz in a strapless Chanel gown.
Solange Knowles in a cosmic-inspired Giles dress.
The pair was chic in black ensembles.
Taraji P. Henson in a strapless Balenciaga dress.
Amal (in a red ruffled Maison Margiela number by John Galliano) and George Clooney hit the red carpet arm-in-arm.
Cher rocked a sequined Marc Jacobs gown.
Common in sleek Prada tux.
The supermodel in an emerald Calvin Klein dress.
Rihanna wowed in Guo Pei Haute Couture.
Lady Gaga in a kimono-style Balenciaga ensemble.
The model in an Alberta Ferretti gown.
The model-turned-actress in a Stella McCartney jumpsuit and unique body art.
The actress in a black Balenciaga number.
The actress wowed in blue beaded Prada.
Gigi Hadid in a bright red Diane von Furstenberg number.
The British couple wowed in Valentino ensembles.
The actress in a custom Louis Vuitton floral frock.
Justin Bieber in Balmain.
The supermodel rocked a black Versace gown.
The actress in a custom Diane von Furstenberg gold gown.
Ellie Goulding, wearing Marchesa, poses with the brand's co-founders founders, Georgina Chapman and Keren Craig.
The divorced couple rocked Valentino on the carpet.
The actress in a structured Roland Mouret gown.
The supermodel in custom Louis Vuitton.
The face of Burberry was decked out head-to-toe in the British label.
The actress wowed in a two-piece Thakoon number.
The starlet stunned in a Fausto Puglisi dress.
Seth Meyers (in Brunello Cucinelli) hit the carpet with wife Alexi Ashe, who wore a Carolina Herrera gown.
Cassie Ventura wowed in a white Zuhair Murad dress while attending the Met Gala with boyfriend Sean Combs.
The actress was cool in J.W. Anderson.
Chrissy Teigen (in a backless St. John Knits dress) and John Legend (in a Gucci tux) hit the carpet.
The Fifty Shades of Grey actress shone in a glittering Chanel mini dress.
FKA Twigs (in a provocative Christopher Kane dress) and Robert Pattinson stepped out at the Met Gala together.
The singer in a red Michael Kors suit.
The performer in a cutout Alexander Wang gown.
The duo, both in Prada, dazzled at the Met Gala.
Reese Witherspoon in a red column dress by Jason Wu.
The singer in a red satin Tom Ford dress.
Jay Z and Beyonce (in custom Givenchy) made a stunning entrance at Monday's gala.