Kim Kardashian Wears Marilyn Monroe's Iconic 'Happy Birthday JFK' Dress At The Met Gala

Kim Kardashian has wowed the crowds at the annual Met Gala by stepping into a piece of American history.

The reality TV star donned the iconic dress Marilyn Monroe wore decades ago to serenade John F. Kennedy for his 45th birthday.

It hasn't been worn since that moment in 1962 and Kim even bleached her hair blonde to complete the look for the evening.

She said it took more than 14 hours to get her luscious locks turned from jet black to Marilyn blonde.

The 41-year-old explained to Vogue the inspiration behind the outfit.

“The idea really came to me after the gala in September last year," she said.

"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.

“For me the most Marilyn Monroe moment is when she sang 'Happy Birthday', to JFK, it was that look.”

When she tried the dress on for the first time, it 'fit like a glove'.

However, the second time was a little bit lacklustre and she discovered she didn't fit into it properly.

That encouraged Kim to undergo a strict diet to ensure she would slip into it perfectly.

John Angelillo/UPI

Because it's a part of American history, no alterations were allowed and the mother-of-four had to put her body through its paces.

She told Vogue: “I would wear a sauna suit twice a day, run on the treadmill, completely cut out all sugar and all carbs, and just eat the cleanest veggies and protein."

She insists she didn't starve herself and was just very strict. When she tried on the dress a month later it fit like a glove again and she said she wanted 'to cry tears of joy when it went up'.

Incredibly, Kim wasn't allowed to even wear the dress for the whole of the Met Gala.

She was simply permitted to put it on (with gloves and no body makeup), walk the red carpet at the Metropolitan Museum of Art, climb the infamous stairs, take a few pictures, and then slip out of the dress.

“I’m extremely respectful to the dress and what it means to American history. I would never want to sit in it or eat in it or have any risk of any damage to it," she explained.

“Everything had to be specifically timed and I had to practice walking up the stairs.”