Kate Middleton Receives Royally Sweet Message From King Charles III on Her 42nd Birthday

A tribute fit for a princess.

In honor of Kate Middleton's 42nd birthday, the Princess of Wales received a shoutout from her father-in-law, King Charles III.

Alongside a photo of the pair shared to the Royal family's official Instagram account Jan. 9, the message noted, "Wishing The Princess of Wales a very happy birthday today!"

The photo—in which Kate is seen grinning from ear-to-ear while sporting a stunning Jess Collett x Alexander McQueen headpiece—was snapped during the king's coronation last May.

As for her birthday plans this year? Kate—who is mom to Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5 with Prince William—is celebrating her big day with a "relaxed and informal tea party" at the family's Windsor's home, per Vanity Fair.

Though this year's festivities may be a little more low-key, Kate has celebrated in epic fashion in years past. In fact, to mark her 40th birthday, Kensington Palace released three new portraits of the royal looking more regal than ever.

After snapping the stunning pics, photographer Paolo Rovers detailed his experience with the then-Duchess of Cambridge.

"I was moved by her warmth and friendly welcome," he shared at the time, "and enchanted by her shining eyes that reflected the loveliness of her soul and her smile showing the generosity of her heart."

He added, "It was a profound and rich experience for me, an unforgettable moment. I have met a wonderful person, a person who, with her positive energy, can bring hope to the whole world."

Keep reading for more of the birthday girl's best looks.

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.

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.

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.

Kate  took the army's salute in a lovely Catherine Walker coat dress, which she paired with matching clutch and shoes.

Kate showed the Americans how it is done in a white gown by Alexander McQueen, the same designer who created her iconic wedding dress.

When in the presence of the Queen it is pretty important to wear your Sunday finest. For the occasion, the Princess of Wales sported a pink coat dress by Alexander McQueen and a fascinator by Juliette Botterill.

For the Chelsea Flower Show, the Duchess of Cambridge wore a whimsical dress from British label Erdem.

Kate wore the matching blazer and skirt combo to The Royal Foundation's Mental Health in Education conference.

The royal stunned in a white McQueen gown for the 2019 BAFTA Awards.

Kate turned heads in this Eponine London dress for Children's Mental Health Week.

The royal looked fabulous in a tweed jacket and boots at Islington Community Garden.

Kate looked gorgeous in a Q by McQueen green and blue tartan coat dress in Dundee, Scotland.

The royal isn't afraid to rock a bold shade, like this pretty magenta she wore to The Royal Opera House.

Kate was all smiles as she watched a flypast to celebrate the centenary of the Royal Air Force.

The mother of three stunned in this number for the Family Action Charity.

Next to Meghan Markle's royal blues, the Duchess of Cambridge's monochromatic ensemble makes a major impact.

Kate took a stroll with Prince William in a coat dress, matching hat and black pumps.

Kate have us major holiday fashion inspo in this green and white L.K. Bennett polka dot dress paired with a khaki clutch and matching heels for a visit to Evelina London Children's Hospital.

The princess looked like a real-life Cinderella at a diplomatic reception in this sparkly Jenny Packham gown that featured sheer cap sleeves and clusters of sequins.

For an official visit to RAF Akrotiri, Kate rocked a business-casual look that included a forest green Smythe blazer paired with navy trousers and a white shirt.

Kate hosted a holiday party in this festive plaid Emilia Wickstead skirt paired with a black Brora cardigan and slouchy black high-heel boots.

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.

Kate stunned in a chic blue coat dress that featured a belted waist, button detailing and a collar paired with matching navy pumps and a black clutch to open the McLaren Automotive's new Composites Technology Centre.

Kate attended the Remembrance Day service in a dark green coat with button detailing and a velvet trim collar, cuffs and pockets, and paired it with a fuzzy headband and carried a black clutch.

For the 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.

The Princess of Wales arrived at Imperial War Museum in a fitted blue sheath dress, nude heels and a matching nude clutch.

In honor of Princess Eugenie's wedding, Kate wore an all-fuchsia ensemble that included a stunning dress and matching fascinator from Alexander McQueen.

The mother of three stunned in a burgundy accented Erdem check print dress paired with a matching clutch and heels.

Kate looked typically elegant for a mental health summit in this beautiful purple Emilia Wickstead dress, nude heels and an Aspinal leather handbag.

The royal's blue taffeta Alexander McQueen gown at the state banquet had all kinds of Disney princess vibes from Queen Mary Lovers Knot tiara to Princess Diana's Collingwood pearl earrings.