Watch Kim Kardashian tackle the Met Gala steps in Marilyn Monroe's £4m dress

Watch now: Pete Davidson helps Kim Kardashian struggle up Met steps in Marilyn Monroe gown

Kim Kardashian won last night's Met Gala red carpet in one of Marilyn Monroe's most iconic dresses.

The star revealed she lost 16lbs in just three weeks to fit into the 60-year-old dress which Monroe famously wore to serenade US President John F Kennedy on his 45th birthday in 1962.

But while she wowed fans with the jaw-dropping look, Kim appeared to struggle to walk up the Met Gala steps - no doubt mindful of the historical worth behind the £4m ($5m) dress.

Attentive boyfriend Pete Davidson was on hand to gently guide Kardashian as she took those tentative steps, while several assistants also came to her aid as made her way carefully upstairs.

Fans flocked to social media to praise the billionaire reality star's look - but also commented on how she struggled to navigate the stairs in the gown.

One tweeted: "I love @KimKardashian's Marilyn look so very much. But you’d think she’d have made sure she could walk up stairs at an event that requires her to… walk up a whole bunch of stairs. With cameras are going off at every second."

Another wrote: "I find it so sweet the way Pete Davidson is helping Kim Kardashian to walk the stairs because her dress is so tight #MetGala."

Kardashian explained there was very good reason for her careful steps in the historic dress that she is the only person ever to wear since Monroe.

"It's 60 years old," Kardashian told La La Anthony during Vogue's live red carpet coverage. "I had this idea to put it on and try it on and then they came with armed guards and gloves. I tried it on and it didn’t fit me."

The dress was based on a sketch by Bob Mackie for the costume designer Jean-Louis and the translucent gown features over 6,000 crystals. Kardashian had to take extra precautions to protect the dress at all costs - arriving at theMetropolitan Museum of Art in a dressing gown to put the dress on in a private fitting room.

Kardashian only wore the dress for her red carpet appearance and to ascend the steps before changing into a replica of the gown once she walked up the stairs, in order to minimise any damage to the fragile 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 and I won’t be wearing the kind of body makeup I usually do," she said. "Everything had to be specifically timed and I had to practice walking up the stairs."

While the dress was first commissioned for Monroe at $1,440, it was later sold for over a million dollars as a part of the actress's estate sale in 1999. In 2016, it was sold at Julien's Auctions for $4.8 million and acquired by Ripley's Believe It Or Not Museum.

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"I’m a big fan of auctions and I own several JFK pieces so I know the owner of Julien’s. He was able to connect me [with Ripley’s] and that’s how the conversation started," Kardashian told Vogue during an exclusive interview on Sunday evening.

Ripley's eventually agreed to loan the dress to Kardashian and flew it out to her home in Calabasas, Los Angeles, to try. The original fitting didn't go as planned.

“I always thought she was extremely curvy. I imagined I might be smaller in some places where she was bigger and bigger in places where she was smaller. So when it didn’t fit me I wanted to cry because it can’t be altered at all," Kardashian told the publication.

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When it came to planning a backup look, she refused to even consider the idea. "It was this or nothing," she said, explaining that she needed to wear "the original naked dress," and was set on doing whatever it took to make it happen.

"I had to lose 16 pounds down today to be able to fit this," she said while chatting with Anthony. "It was like a role. I was determined to fit it."

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With no alterations allowed on the historic dress, Kardashian committed to make it fit, running on the treadmill twice a day in a sauna suit, cutting out all sugar and carbs and instead eating lean protein and vegetables.

She also spent 14 hours dyeing her black tresses blonde the day before the event in order to complete her Monroe transformation.

Her efforts were worth it though as she - and the dress - were the stand-out stars of the red carpet.