US socialite Kim Kardashian arrives for the 2021 Met Gala at the Metropolitan Museum of Art on Sept 13, 2021, in New York. (ANGELA WEISS / AFP)

NEW YORK - Red, silver and blue ruled the Metropolitan Museum of Art steps at a youth-driven Met Gala on Monday in a celebration of the best of American fashion.

The invitation-only gala is a fundraising benefit for New York's Metropolitan Museum of Art and also marks the opening of the Costume Institute's annual fashion exhibition which this year is titled In America: A Lexicon of Fashion

There were show-stopping outfits from rapper Lil Nas X, wearing a Versace suit of gold armor and supermodel Iman in a stunning feathered gold and beige headdress and cage skirt as actors, singers, sports stars and social media influencers embraced the theme of "American Independence."

Kim Kardashian, wearing Balenciaga, turned heads by dressing entirely in black, with even her face covered in thick black fabric. Her companion, a man wearing a blackout hoodie, was initially thought to be her estranged husband Kanye West, but Vogue.com said later it was Balenciaga designer Demna Gvasalia.

Rihanna, one of the most anticipated Met Gala stars, arrived fashionably late about 45 minutes after the rest of the guests had gone inside. The Diamonds singer wore an oversized black coat dress, topped off with a beanie.

Chaired by four of the biggest Gen Z stars - actor Timothee Chalamet, singer Billie Eilish, poet Amanda Gorman and tennis champion Naomi Osaka - the so-called Oscars of the East Coast annual fundraiser was intended to highlight young designers and celebrities.

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US rapper Lil Nas X arrives for the 2021 Met Gala at the Metropolitan Museum of Art on Sept 13, 2021, in New York. (ANGELA WEISS / AFP)

Dune star Chalamet sported a white silk suit with black lapels, teamed with white high-top sneakers, while Eilish, 19, shed her trademark baggy clothes for a plunging Oscar de la Renta peach gown she said was inspired by Marilyn Monroe.

The invitation-only gala is a fundraising benefit for New York's Metropolitan Museum of Art and also marks the opening of the Costume Institute's annual fashion exhibition which this year is titled In America: A Lexicon of Fashion.

Some guests took the theme more seriously than others. Jennifer Lopez sported a Western black hat over a plunging bronze gown and fur jacket, singer Leon Bridges had a white cowboy hat and fringed suede jacket, Kim Petras wore the model of a horse's head on her bust, Blondie singer Debbie Harry picked a gown inspired by the US flag, and Dear Evan Hansen star Ben Platt chose denim flares and 1970s platform shoes.

Gorman wore a blue Vera Wang gown and crystal laurel headpiece she said was intended to make her look like a reimagined Statue of Liberty, while red was the choice of multiple celebrities, including model Karlie Kloss, actress Jennifer Hudson and Colombian singer Maluma.

Amid the glamour, some guests highlighted social issues.

Barbadian singer Rihanna and US rapper A$AP Rocky arrives for the 2021 Met Gala at the Metropolitan Museum of Art on Sept 13, 2021, in New York. (ANGELA WEISS / AFP)

Soccer player Megan Rapinoe carried a clutch bag with the words "In gay we trust," while Schitt's Creek actor Dan Levy opted for a bold, puff-sleeved creation featuring artwork on the front that showed two men kissing.

Alexandria Ocasio-Cortez, the 31-year-old Democratic Congresswoman from New York, had "Tax the Rich" written in red across the back of her white gown.

"It's time we bring all classes into the conversation about having a fairer country," Ocasio-Cortez said about the slogan.

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Like Ocasio-Cortez, many of the celebrities were first-timers at the Met Gala, including YouTuber Emma Chamberlain, Tik Tok star Addison Rae, musician Chance the Rapper, singer Olivia Rodrigo and Game of Thrones actress Maisie Williams.

Last year's Met Gala was canceled because of the coronavirus pandemic, and Monday's gathering was about a third smaller than usual with about 300 guests, with proof of vaccination required, though they did not wear masks while posing upon their arrival.

Grimes, the musician girlfriend of Tesla entrepreneur Elon Musk, was among the exceptions. She sported a metallic face mask and carried a sword.

US singer Jennifer Lopez arrives for the 2021 Met Gala at the Metropolitan Museum of Art on Sept 13, 2021, in New York. (ANGELA WEISS / AFP)