A US museum has denied claims that Marilyn Monroe’s Happy Birthday gown was damaged after Kim Kardashian wore it to this year’s Met Gala.

Ripley’s Believe It Or Not! has also defended its decision to loan the pricey piece of fashion history to Kardashian for the prestigious red carpet in May.

It was the first time the custom-made dress had been worn since 1962, when Monroe famously sang Happy Birthday to then US president John F Kennedy. The museum splashed out a record-breaking $US4.8 million ($6.7 million) to buy the gown in 2016.

This week there was uproar when photos emerged appearing to show significant damage to the dress after its Met Gala outing.

One side-by-side comparison claimed to show the dress in 2016, and then after Kardashian wore it in New York. The photos showed missing crystals and the delicate fabric stretched and torn.

Additional images have since been shared online by author Darrell Rooney, showing apparent damage to its right shoulder strap.

But Ripley’s has denied the reality star damaged the dress, defending Kardashian – and its decision to lend it to her.

“Kim Kardashian wearing the dress has been hotly contested, but she did not personally damage the garment in the short amount of time it was worn at the Met Gala,” it said on social media on Thursday (US time).

The museum said the garment was already damaged, referring to a condition report from 2017.

“[It] states ‘a number of the seams are pulled and worn. This is not surprising given how delicate the material is. There is puckering at the back of the hooks and eyes’, among other instances of damage,” it said.

The museum acknowledged there was “calculated risk” associated with wearing the fragile dress, but insisted it did all it could to preserve the garment.

“No matter which side of the debate you are on, the historical importance of the dress has not been negated, but rather highlighted,” it said.

Kardashian admitted in a red carpet interview that Monroe’s dress was a squeeze, revealing she shed more than seven kilograms in just three weeks so it would fit. She was still unable to do the zip up all the way, so wore a white shawl to conceal the unclasped back.

Footage from Kardashian’s Met Gala fitting also showed Ripley’s staff struggling to pull the gown over her hips and waist.

Ripley’s vice president of publishing and licensing Amanda Joiner issued her own a statement, saying the dress was returned in “the same condition it started in”.

Kim Kardashian attends the 2022 Met Gala in Marilyn Monroe’s gown alongside boyfriend Pete Davidson.

But the museum’s defence has done little to quell the outrage. Angry fans still say Kardashian should never have worn Monroe’s dress.

“The dress was damaged. Trying to gaslight us all into believing it’s not is disgusting and just going to make people more mad,” one wrote online.

“We all saw the video of your team tugging and manhandling this historic garment over that woman’s body when it was clear it wasn’t going to fit. You damaged the dress full stop,” said another.

Marilyn Monroe Collection, the Instagram account that made the first claims of damage, also reacted to Ripley’s defence.

“It’s never been implied that the gown was in perfect condition. My own photos show some crystals missing prior to the auction. However, it’s significantly more today,” a post read.