Kate Middleton brings back Princess Diana's famous tiara for glamorous night alongside Prince William

When you find a tiara you love, you stick with it.

Kate Middleton brought out a royal favorite for the latest state banquet, once again dazzling in the sparkling headpiece that has become her go-to for palace glamour.

On Oct.

20, the Princess of Wales joined her husband, Prince William, to help King Charles and Queen Camilla host Sultan Haitham bin Tarik of Oman for his state visit to the U.K. at Windsor Castle.

For the glamorous evening, the mother of three wore her go-to headpiece: Queen Mary's Lover's Knot tiara, which she has worn numerous times since 2015.

KATE MIDDLETON WEARS PRINCESS DIANA'S PEARL BRACELET AT TROOPING THE COLOUR AS CHARLOTTE MIRRORS HER MOTHER The 44-year-old completed her look with a flowing, sunshine-yellow gown by Elie Saab, King Charles' Royal Family Order badge and the Royal Victorian Order sash and star.

"Kate is wearing what I like to call her 'old faithful,'" royal commentator Amanda Matta told Fox News Digital.

"It has truly become her signature piece of royal jewelry, and it speaks to her constancy as a part of the modern monarchy .

Paired with a new beautiful gown for the formal occasion, a repeat tiara keeps the entire look from overshadowing the visiting Sultan of Oman and the true hosts of the evening: King Charles and Queen Camilla." WATCH: KATE MIDDLETON IS THE MONARCHY'S SECRET WEAPON: AUTHOR "I always come back to what a perfect piece this was for Kate to pull off all those years ago when she first wore It," said Matta.

"It's a very romantic piece, tying in nicely with the sentimentality of William and Kate's royal love story." Since Kate married Prince William in 2011, she has worn five different royal tiaras, with the Lover's Knot appearing to be her favorite.

The sparkler is a replica of an earlier piece, Town & Country reported.

According to the outlet, it was created for Queen Mary in 1913 by the House of Garrard using pearls and diamonds already owned by her family.

Mary modeled it after a tiara owned by her grandmother, Princess Augusta, Duchess of Cambridge.

The original tiara is believed to be held in a private collection.