For Kate Middleton, there's one royal jewel that reigns supreme.
The Princess of Wales reached for her tried and true accessory, the famed Queen Mary's Lover's Knot tiara, for her and husband Prince William's state banquet with Sultan Haitham bin Tariq of Oman Oct. 20.
In addition to the spectacular headpiece, which features 19 arches and 28 drop-shaped pearls, Kate donned a flowy yellow gown by Elie Saab featuring a braided collar, keyhole cutout and chiffon cape. She completed her majestic look with earrings and a diamond bracelet that once belonged to the late Queen Elizabeth II, as well as the Royal Family Order sash and the Royal Victorian Order star.
This marks the 16th time that Kate has worn the Lover's Knot—the most out of all the tiaras in the royal collection—since marrying William in 2011.
Crafted in 1913, the diadem was made for Queen Mary as a copy of another piece belonging to Princess Augusta of Hesse-Kassel, who was named the Duchess of Cambridge—a title Kate also holds—in 1818.
But there may be a sentimental reason as to why the Lover's Knot takes the crown in Kate's eyes. As former royal butler Grant Harrold previously noted, the tiara was one of Princess Diana's "favorite pieces" before her 1997 death.
"I believe Kate wears this to keep her late mother-in-law’s memory alive,” he told InStyle in March. “Kate will know how much William misses his mother, so I think she makes a conscious effort to incorporate elements of her during her time as Princess of Wales."
“There are obviously many comparisons between the two royal women, and this is a way Kate can ensure people continue to talk about and remember Diana,” he continued. “I think it’s very clever and special and shows how thoughtful Kate is.”
And the connection to Diana doesn't stop there. After all, the Lover's Knot was made by Garrard, the same jeweler behind Kate's 12-carat sapphire engagement ring previously owned by the People's Princess.
"It’s obviously a favorite of Kate’s, and it’s easy to see why, as it’s an incredible piece of jewelry," Harrold said of the Lover's Knot. "However, I believe there is a stronger, more emotional reason why we’ve seen her wearing it so often since she joined the royal family. It’s very much a tribute to Diana."
To see more of Kate's memorable fashion moments through the years, keep reading...
Princess of Style
Shortly after succeeding the Princess of Wales title, Kate wore this stunning Jenny Packham gown with Queen Mary's Lover's Knot Tiara to a state dinner in 2022.
Christmas Cheer
Kate Middleton's color palette was muted but she radiated joy all the same during the royal family's walk to church on Christmas morning in 2025, her return to the annual tradition after celebrating the holiday privately with Prince William and their kids the previous year.
Royal in Red
For a Diplomatic Corps reception at Buckingham Palace in December 2022, the Princess of Wales styled her sparkly Jenny Packham gown with several regal accessories, including Queen Elizabeth II's Royal Family Order badge, the sash and star of the Royal Victorian Order, diamond frame earrings, a diamond Art Deco brooch and Queen Elizabeth the Queen Mother's famed Lotus Flower Tiara.
Vision in White
There's nothing more refreshing than seeing a royal who isn't afraid to wear an item on numerous occasions. The royal last wore this Barbara Casasola number at the 2016 for the Art Fund awards.
Elegance at Work
Kate took the army's salute in 2019 while sporting a lovely Catherine Walker coat dress, which she paired with matching clutch and shoes.
Flaunt It
Kate showed the Americans how it is done in a white gown by Alexander McQueen, the same designer who created her iconic wedding dress, during a state banquet with Steven Mnuchin in 2019.
Tea Party Ready
When in the presence of the Queen, it is pretty important to wear your Sunday finest. In 2019, the Princess of Wales sported a pink coat dress by Alexander McQueen and a fascinator by Juliette Botterill.
Boho Chic
For the 2019 Chelsea Flower Show, the Duchess of Cambridge wore a whimsical dress from British label Erdem.
Sophisticated Suits
Kate wore a matching blazer and skirt combo to The Royal Foundation's Mental Health in Education conference in 2019.
Gorgeous Gowns
The royal stunned in a white McQueen gown for the 2019 BAFTA Awards.
Going Green
Kate turned heads in this Eponine London dress for Children's Mental Health Week 2019.
Cute and Casual
In 2019, 5he royal looked fabulous in a tweed jacket and boots at Islington Community Garden.
Pretty in Plaid
Kate looked gorgeous in a Q by McQueen green and blue tartan coat dress during a visit to Scotland in 2019.
Bold and Beautiful
The royal isn't afraid to rock a bold shade, like this pretty magenta she wore to The Royal Opera House in 2019.
Beautiful in Blue
Kate was all smiles as she watched a flypast to celebrate the centenary of the Royal Air Force in 2018.
Elegant in Emerald
The mother of three stunned in this number for an event with Family Action Charity in 2019.
Royal Red
Next to Meghan Markle's royal blues, the Duchess of Cambridge's monochromatic ensemble made a major impact in 2018.
Teal Time
In January 2019, Kate took a stroll with Prince William in a coat dress, matching hat and black pumps.
Festive and Chic
Kate was a major holiday fashion inspo in this green and white L.K. Bennett polka dot dress paired with a khaki clutch and matching heels during a 2018 visit to Evelina London Children's Hospital.
Cinderella Story
The princess looked like a real-life Cinderella at a 2018 diplomatic reception in this sparkly Jenny Packham gown that featured sheer cap sleeves and clusters of sequins.
Fabulous Flare
For an official visit to RAF Akrotiri in 2018, Kate rocked a business-casual look that included a forest green Smythe blazer paired with navy trousers and a white shirt.
Pleasant in Plaid
Kate hosted a 2018 holiday party in this festive plaid Emilia Wickstead skirt paired with a black Brora cardigan and slouchy black high-heel boots.
Burgundy Beauty
In 2018, the royal visitsed UCL Developmental Neuroscience Lab at UCL London in a burgundy Paule Ka blazer and skirt paired with a black turtleneck, tights and heels.
Buttoned and Belted
Wearing a chic blue coat dress with matching navy pumps and a black clutch, Kate stunned during the 2018 opening of McLaren Automotive's Composites Technology Centre.
Velvet Trim
Kate attended a 2018 Remembrance Day service in a dark green coat with button detailing and a velvet trim collar, cuffs and pockets. She paired the jacket with a fuzzy headband and carried a black clutch.
Aquamarine Dream
For the 2018 Tusk Conservation Awards, Kate wore her aquamarine Jenny Packham gown (a stunning look she's worn before) paired with diamond chandelier earrings, a matching clutch and Jimmy Choo pumps.
Nice in Navy
The Princess of Wales arrived at Imperial War Museum in 2018 clad in a fitted blue sheath dress, nude heels and a matching nude clutch.
Royal Wedding Style
For Princess Eugenie's 2018 wedding, Kate wore an all-fuchsia ensemble that included a stunning dress and matching fascinator from Alexander McQueen.
Chic in Check
In 2018, the mother of three stunned in a burgundy accented Erdem check print dress paired with a matching clutch and heels.
Lady in Lavender
Kate looked typically elegant for a 2018 mental health summit in this beautiful purple Emilia Wickstead dress, nude heels and an Aspinal leather handbag.