Although Kate Middleton and Meghan Markle made waves with their wedding dresses and accessories, people still can't help but be reminded of another bride whenever a royal wedding takes place.

One of the most iconic royal weddings (it was watched by almost one billion people) in recent memory was the late Princess Diana's nuptials to Charles, the Prince of Wales on 29 July 1981.

Diana said "I do" in one of the most unique dresses ever made. The custom-made ivory silk tafetta gown by David and Elizabeth Emanuel featured antique lace, sequins, hand embroidery, and 10,000 pearls.

While the voluminous gown was hard to ignore, there was another part of her outfit that had people's attention: the Spencer Tiara.

The stunning headpiece has been in the Spencer family for decades. It was gifted to Diana's grandmother, Lady Cynthia Hamilton when she married Albert, Viscount Althorp in 1919.

It was Albert's great aunt, Lady Sarah Isabella Spencer that gave Cynthia the center part of the topper shortly before she died that same year.

The current version of the sparkler, which is made up of various pieces of jewelry, including diamonds from Frances Manby, the Viscountess of Montague, was believed to have been finalized in the 30s, and it has since become the wedding tiara for the Spencers.

While Princess Diana's mother, Frances, did not wear it, her sisters, Lady Sarah and Jane, Baroness Fellowes, have both worn it on their wedding days. Diana's brother's first bride, Victoria Lockwood, also opted for the headpiece when she married into the aristocrat family back in 1989.

Of course, the tiara become more recognizable when Diana chose it over the Queen Mary's Lover's Knot Tiara for her big day. She also wore it on multiple outings after becoming a member of the royal family.

After her tragic death in 1997, the tiara was seen at various Diana-themed exhibits, but it was never publicly worn, until now.

Many were hoping the jewel's reappearance would be on Kate or Meghan, but it was fittingly brought back by someone even closer to the late princess: her niece.

On June 16, Celia McCorquodale wed her beau George Woodhouse, and for the first time in 21 years, the Spencer Tiara was seen on someone other than her late aunt.

Celia chose to walk down the aisle with the special piece on her head not only to carry on the Spencer family tradition, but also as a nod to her aunt, who considered it one of her favorites.

Celia and George were surrounded by their closest family and friends, including older cousin Prince Harry and his new wife Meghan.

Harry, 33, wore a three-piece-suit with a blue tie that matched his wife's dress.

Meghan, 36, wore a $5,490 long-sleeve blue and white floral print Oscar de La Renta dress. She accessorized it with a white fascinator and the same heels she wore at her own wedding.

Unfortunately, her effort wasn't as acclaimed as her recent outfits. The media and people on the internet were quick to mock and criticize her attire.

"Oh no sorry #MeghanMarkle this is not you... way too big!! Where has your lovely style gone ?" tweeted one user.

"I have tried giving her credit, but #MeghanMarkle simply cannot get it right. Here is "the thing" she was wearing this weekend. I am sure Mr Oscar de la Renta is turning in his grave..." wrote another.

One Twitter user compared the dress to his IKEA bed sheets: "Not criticising Meghan Markle's dress from the wedding yesterday in any way but literally have her dress as my bed sheets from @IKEAUK."

Someone went as far as calling the new Duchess of Sussex a "sack of potatoes," while another said that Meghan's dress reminded her of a scene from Gone with the Wind.  

"#Meghan Markle - looks like she re-inacted the Gone with the Wind scene where Scarlett makes a dress from old curtains. Megan only had a M&S duvet to work with."

A few days after what many considered a fashion-faux pas, Meghan redeemed herself by channeling Audrey Hepburn at her first Royal Ascot as a duchess.

The former actress wore a chic black and white ensemble by Givenchy, the same design house that created her wedding dress.

Meghan has a lifetime of royal duties to dress up for, so one miss is not a big deal.