Carole Middleton undergoes Hollywood transformation in rarely-pictured second mother-of-the-bride dress

The Princess of Wales made a much-anticipated outfit change on her wedding day with Prince William, swapping her lace Alexander McQueen wedding dress for a belted evening gown.

But she wasn't the only one to switch up her look. After the royal couple's ceremony at Westminster Abbey and lunch reception hosted by the late Queen Elizabeth at Buckingham Palace, the bride and groom as well as their guests retired to their own quarters to freshen up for the evening party.

As Kate and William prepare to mark their 13th wedding anniversary, we can't help but wonder what Kate's inner circle, the Middleton family, wore to the private evening, attended by 300 guests.

While very few post-wedding photos exist, one rare snap captured Carole in her uber-glamorous second mother-of-the-bride outfit. She had swapped her demure pastel blue dress and matching coat from Catherine Walker for a Hollywood-worthy black floor-length gown.

Features included a low V-neck, pleated flutter sleeves, a belted waist and a tiered skirt, and Carole recycled the gown for the British Red Cross International Fundraising Committee Ambassadors' gala in London in 2013.

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For the royal wedding appearance, she amped up the drama with a sparkling necklace and drop earrings. In order to fully display the latter, the Party Pieces founder had swept her shoulder-length hair into an intricate updo finished with sparkly hair accessories, while her fringe remained down to frame her face.

Carole stood next to her other daughter, Pippa, who had acted as maid of honour for Kate. After causing a stir in her figure-skimming white cowl-neck bridesmaid dress, Pippa slipped into a much bolder hue to celebrate her sister and new brother-in-law's nuptials.

She rocked an emerald green dress with a plunging neckline and thick straps, finished with Grecian embellishments under the bust and on the shoulders. Unlike her mother, who had switched up her beauty look, Pippa kept her hair in the half-updo with cascading curls she had been wearing for the ceremony.

Carole later admitted that she wasn't overly stressed about the royal wedding, despite the fact that it was such a high-profile occasion streamed on TV across the world.

After confessing she "hates" shopping, she told The Telegraph in an interview: "Like every mother, I wanted to look my best, make my children proud and enjoy the day. I honestly don’t think I was any more stressed than any other mother-of-the-bride."

In the same chat, Carole shared some behind-the-scenes details about the planning that went into the nuptials.

"We talked about music… everything. I was involved lots with both Pip’s and Catherine’s weddings," the mother-of-three said.

Carole added that she had learnt some key lessons in the preparation process, including "don't muscle in on the guest list." She continued: "But I think the most important thing, as a parent, is to listen to what your daughter wants. You can have all the ideas in the world, but it has to be about them. And don’t muscle in on the guest list."

By comparison, Carole enjoyed a much more low-key wedding with her husband Michael in June 1980.

Kate's parents exchanged vows in Buckinghamshire before enjoying a simple "bonfire" and chilli con carne in the evening.

Carole wore a boho bridal gown with a Bardot neckline and embroidered ruffle detailing which were revealed in her son James Middleton's wedding photos after she lent the frock to her daughter-in-law Alizee Thevenet.

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