In December, The Duchess of Cambridge dazzled when she attended the Queen's Diplomatic Reception, an annual white tie affair held at Buckingham Palace.
The mother-of-three oozed regal glamour in Princess Diana's tiara - the Cambridge Lover's Knot and an ice-blue Jenny Packham gown as she greeted foreign diplomats and ambassadors alongside the Queen, Prince Charles, Duchess Camilla and Prince William.
This marked the ninth time Catherine has ever worn a tiara.
Indeed, fans rejoice every time Kate wears Princess Diana's favourite sparkling headpiece.
We couldn't get enough of the new photos because let's face it, you'll be hard pressed to find The Firm drenched in their bling, save for very important occasions.
While we'd like to think Kate and co. can simply dip into The Queen's bottomless jewellery box whenever they fancy, it's sadly not as simple as that!
Royal etiquette has adapted with the modern times and these days, tiaras are only worn for weddings, state banquets or official receptions. Keen to steer their image away from decadence and indulgence, you'll be more likely to see The Queen horse riding in jodhpurs, Kate recycling a dress several times over and Princess Charlotte in Prince George's hand-me-downs.
Still, there's no denying just how exciting it is to see a princess in a tiara.
Most recently, Duchess Meghan and Princess Eugenie both stunned on their wedding days with ornate headpieces lent from The Queen's collection.
Meghan opted for the Queen Mary Diamond Bandeau while Eugenie donned the Greville Emerald Kokoshnik Tiara.
"The first time a tiara is worn is by the bride on her wedding day. It signals the crowning of love and the loss of innocence to marriage. The family tiara is worn by the bride and from that moment onwards it was the groom's jewellery she was expected to wear. It was a subliminal message that she had moved from her family to another," Geoffrey Mun explains in his book Tiaras - A History of Splendour.
"Nowadays few adhere to this protocol, even if they are aware of it."
In fact, Duchess Catherine has only ever worn a tiara in public seven times - including her wedding day.
Keep scrolling to see every single photo of the Duchess in a tiara!
Kate Middleton's "something borrowed" for her 2011 wedding day happened to be this incredible creation made of diamonds and platinum, which The Queen very kindly lent to her.
King George VI commissioned Cartier to make it in 1936 as a gift to his wife, Queen Elizabeth (aka The Queen Mother). She handed it down her daughter, Princess Elizabeth, for her 18th birthday and it's been in The Queen's collection ever since.
WATCH: Kate and William exchange vows. Post continues after the video...
Kate waited two whole years after tying the knot to wear another tiara, this time stepping out in the Lotus Flower (also referred to as the Papyrus Tiara) for a diplomatic reception at Buckingham Palace.
Tucking the glittering number neatly on top of her flowing locks, its papyrus-shaped folds and diamond and pearl accents utterly popped.
This particular number originally belonged to The Queen Mother before The Queen inherited it.
Kate's ravishing red look stole the show at Buckingham Palace's state banquet to celebrate Chinese President Mr Xi Jinping's visit in October 2015.
Sitting pride of place on her swept back locks was the trusty old Lotus Flower.
It's somewhat of tiara staple for Kate now, but the first time we ever saw her don the iconic Cambridge Lover's Knot tiara was back in 2015 for the diplomatic reception at Buckingham Palace.
The showstopping tiara is an heirloom headpiece which The Queen inherited it from her grandmother Queen Mary, before giving it to Princess Diana as a present on her wedding day in 1981.
It was worn by Diana on many occasions but returned to the monarch when Princess Diana and Prince Charles divorced in 1996.
It doesn't get much better than this! A princess, her prince and a sparkling tiara in all its glory.
The 36-year-old once again sported the The Cambridge Lover's Knot masterpiece for the 2016 annual diplomatic reception.
In July last year, the mother-of-two dusted off the Cambridge Lover's Knot for a third time when she attended a lavish state dinner at the palace held in honour of King Felipe VI and Queen Letizia of Spain.
Dripping in a ruby and diamond necklace on loan from the monarch, Kate completed her look with a custom-made lilac Marchesa dress.
WATCH: The Royal Family arrive to the state dinner. Post continues...
Last December marked the seventh time Kate has ever worn a tiara in public, and if you ask us she should do it more often!
The Duchess of Cambridge clearly has taken a liking to The Cambridge Lover's Knot and opted to wear it to the 2017 diplomatic reception.
Although only the top of her gown could be seen as she arrived in a chauffeur-driven Bentley, fans were given a glimpse of her embellished white dress.
The mother-of-three's brunette locks were swept up into an elegant chignon so her impressive diamond jewels could take pride of place.
When The Queen threw a State Banquet for Queen Maxima and her husband, King Willem-Alexander, of the Netherlands' visit to the UK this October, Duchess Catherine stole the show.
Atop of the Duchess of Cambridge's brunette locks was her late mother-in-law Princess Diana's tiara - the Cambridge Lover's Knot.
Kate finished off her regal look with Princess Diana's Collingwood pearl earrings, a diamond bracelet and an ornate pearl necklace, which was a wedding present from Queen Alexandra.
But it was what Catherine had pinned on her dress that truly delighted royal watchers.
In an historical moment, the 37-year-old wore the Royal Family Order of Queen Elizabeth II badge, which features the monarch's portrait on a yellow ribbon.
The Royal Family Order of Queen Elizabeth II is an honour given to female members of the British Royal Family from The Queen and is worn for special, formal events - such as a State Banquet.
Dressed in a stunning Jenny Packham gown, the Duchess of Cambridge once again wore the Cambridge Lover's Knot tiara for the Queen's Diplomatic Reception.
Of the nine times Duchess Catherine has worn a tiara, five of those occasions have seen her wear the Cambridge Lover's Knot so it's clearly a top pick and a sweet tribute to her late mother-in-law, Princess Diana.
Catherine also re-wore Princess Diana's Collingwood pearl earrings and had the honour of once again wearing the Royal Family Order of Queen Elizabeth II.
It's clear the Duchess has made a great impression on her regal grandmother-in-law.