Kim Kardashian wears Marilyn Monroe's iconic 'Happy Birthday, Mr. President' dress to the Met Gala

Kim Kardashian wore Marilyn Monroe’s iconic gown, from when she performed “Happy Birthday, Mr. President,” to this year's Met Gala, confirming a widespread fan theory about what she'd sport for fashion's biggest event of the year.

This year's Met Gala theme is "In America: An Anthology of American Fashion." Guests were encouraged to emulate "gilded glamour."

Monroe's dress was ahead of its time, Kardashian, 41, told Vogue in an interview published just before she appeared on the carpet. She said the idea came to her after last year's gala in September, when she wore a head-to-toe black Balenciaga look (which inspired Met Gala memes).

"I thought to myself, what would I have done for the American theme if it had not been the Balenciaga look? What’s the most American thing you can think of? And that’s Marilyn Monroe,” Kardashian said.

Monroe's dress, which she wore to President John F. Kennedy’s birthday fundraiser in 1962, is one of the most recognizable outfits from American history. Designed by Jean Louis, the sleek backless gown includes 2,500 hand-stitched crystals. Monroe was reportedly sewn into the dress for a seamless fit. It was one of Monroe's last public appearances before her death less than three months later.

"Nowadays everyone wears sheer dresses, but back then that was not the case," she said to Vogue. "In a sense, it's the original naked dress. That's why it was so shocking."

Kardashian had been hinting at wearing the vintage piece for weeks. During the red carpet premiere of Hulu's "The Kardashians" last month, she told Access Hollywood that her Met Gala attendance depended on her dress fitting.

"It really depends if I fit into my dress, so I hope I'm going," Kardashian said. "I think it will be up to the last minute because it can't be tailored, so I have to fit into it like exactly."

Kardashian and her boyfriend Pete Davidson were spotted leaving "Ripley's Believe It or Not!" museum last month, the Sun reported. Ripley's bought the dress from a 2016 auction for $4.8 million, and displays it at its Orlando, Florida, location.

That reported visit, as well as Kardashian's legacy of wearing skintight dresses and her comments alluding to dress fittings, clued fans into her Met Gala outfit.

Kardashian first tried on a replica of the dress, which "fit perfectly," she told Vogue. The original dress was shipped to her home in Calabasas, California, via private plane, where she had to wear gloves to try it on.

"So when it didn't fit me I wanted to cry because it can't be altered at all," she said.

To wear the dress, Kardashian said she wore a "sauna suit twice a day," exercised daily and adhered to a strict diet devoid of sugar and carbs.

"I didn't starve myself, but I was so strict," Kardashian said. "I wanted to cry tears of joy when it went up."

On the red carpet, she told Vogue she lost 16 pounds to fit into the dress. “It was such a challenge, it was like a role. I was determined to fit it.”

Given the fragile nature of the gown and its historical significance, Kardashian said she only plans to wear "the original dress for a matter of minutes." She changed into the dress itself at a special fitting room at the base of the Met Gala steps, with a Ripley's conservationist assisting her.

"I'm extremely respectful to the dress and what it means to American history," Kardashian said. “Everything had to be specifically timed and I had to practice walking up the stairs."

The gown is "now valued at over $10 million," according to Ripley’s Believe It or Not!.

In a post on its website, Ripley’s Believe It or Not! said "Marilyn Monroe’s “Happy Birthday” dress — now also Kim Kardashian’s 2022 Met Gala look — will be on display at Ripley’s Believe It or Not! Hollywood for a limited time beginning Memorial Day weekend."