On Monday evening, Kim Kardashian wowed the world by stepping onto the Met Gala red carpet in the same dress Marilyn Monroe wore to serenade President Kennedy in 1962.

The glittering gown - which was loaned to Kim by Ripley's Believe It Or Not! museum - is an iconic piece of American history that fetched a whopping $4.8 million at auction and hasn't been worn since Marilyn donned it in the 1960s.

But it turns out that squeezing into the dress was no small feat.

In brand new footage, fans have been given a behind-the-scenes peek at the difficult task Kim's team faced when it came to getting her - and her famous butt - into the garment.

Because it is such a valuable artifact, the gown couldn't be altered to better fit the reality TV star. This meant that in order to wear it to the Met, Kim had to go on a strict crash diet that ultimately saw her drop 16 pounds in just a few weeks.

So when it came to a fitting just 10 days before the Gala, she was understandably determined to make the look work. In the behind-the-scenes clip shared by TMZ, Kim can be seen visiting Ripley's museum - where the dress is kept safe in a temperature-controlled vault - waiting nervously to try on the glittering gown.

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Surrounded by a team of helpers (including her comedian boyfriend Pete Davidson and hairstylist Chris Appleton) Kim steps into the dress while gloves assistants shimmy it up her legs. They run into a spot of trouble when they reach her butt, and the reality star jokes: "Dear Lord, should we sing 'Hallelujah' or something?"

But with the help of Chris's encouraging instructions - "Kim, push it! Push your a**!" he cheers - the team manages to get the gown all the way up her body. One problem still remains - they can't do up the zip.

Kim, however, is unfazed and, while inspecting the partially undone fastening, suggests an alternative. "Can we use that tie and tie it and keep it open?" she said, adding: "What if we did that and put a fur over?"

All that's left to do is throw an elegant white fur shawl over her shoulders, and the look is complete. After practicing walking up the stairs (using Pete's arm for support) Kim's transformation into Marilyn is complete and she's all ready to head to the ball.

Kim [[imagecaption|| Kim Kardashian and Pete Davidson. Credit: Doug Peters / Alamy]]

Featured Image Credit: Doug Peters / Alamy

Video shows Kim Kardashian's team helping her into Marilyn Monroe iconic dress