Duchess Kate's First State Banquet: Diamonds and Dresses the Duchess Might Wear

— -- Diamonds are a girl's best friend, so what is a future Queen of England to do when she attends her first state banquet? Obviously, turn to the queen, who has one of the most dazzling collections of diamond tiaras in the world.

Should the Duchess of Cambridge wear a tiara to tonight's state banquet with the president of China, and most bets are she will, it will be only the third time we've seen Duchess Kate showcase one of the British royal family's priceless treasures.

Here are the options before the 33-year-old duchess as she decides which, if any, tiara she will wear to greet China's leader.

Cartier Halo Tiara

Kate could opt for the Cartier Halo tiara, which she wore on the occasion of her 2011 wedding to Prince William. The headpiece, lent to Kate for the wedding by Queen Elizabeth, was passed down through the Windsor family and was a gift to then-Princess Elizabeth on her 18th birthday. It features 739 brilliant and 149 baton diamonds.

Lotus Flower Tiara

The Duchess of Cambridge borrowed this piece from the queen in 2013 to wear to the queen's diplomatic reception, marking the second time Kate debuted a tiara. The tiara is not as heavy as some of the other tiaras in her majesty's collection and so is deemed suitable for a long event where a tiara can become so heavy it becomes uncomfortable by night's end.

Cambridge Lovers Knot Tiara

This exquisite tiara was a wedding present from the queen to Princess Diana. Given the association with William's mother, the late Princess of Wales, and the Cambridge name, there's a distinct possibility the duchess may choose this stunning tiara.

One of the most famous tiaras, it was commissioned by Garrard from Queen Mary in 1913-1914. The tiara consists of 19 hanging pearls in between a diamond arch and lovers knot bow. Princess Diana wore it often but it's very heavy, reportedly giving her headaches, so she frequently used her family's Spencer tiara instead.

Spencer Tiara

Princess Diana wore this tiara on her wedding day, to Prince Charles, in 1981.

Vladimir Tiara

One of the queen's favorite pieces, the Vladimir tiara is sometimes confused with the Cambridge Lovers Knot tiara to the untrained eye. It is made of 15 hanging drop pearls in between intertwined diamond circles. Garrard adopted the tiara for the queen so she could interchange the pearls with the Cambridge emeralds. Because of the association with the Cambridge name, this tiara is a possibility, but given that it's one of her majesty's favorite pieces, it's more likely she would wear it herself than Prince William's wife.

Queen's Sapphire Tiara

This sapphire and diamond tiara was made and designed by Garrard in 1963 at her majesty's request. The queen wears it often with a matching sapphire necklace and it would certainly complement Kate's sapphire engagement ring, which Princess Diana previously owned.

If the duchess borrows from the queen's sapphire collection, it's possible we could see one of Diana's signature necklaces, the pearl and sapphire choker she wore frequently.

Kate's Gown

In addition to the jewels, what about the all-important frock? Evening gowns are de rigeur for the event and Kate could pick one of her favorite go-to designers. Sarah Burton for Alexander McQueen, who designed her wedding dress, and Jenny Packham are firm favorites, as is Emilia Wickstead, another British designer whom Kate has favored.

Kate likes to showcase designers associated with the people she's entertaining so she may opt for a Chinese designer when she attends the banquets for China's president and first lady. Jason Wu has Taiwanese ancestry so is probably less likely but has been a favorite of U.S. First Lady Michelle Obama.

The Duchess of Cambridge raised the profile of Prabal Garung in 2012 when she was in Singapore, making him a household name. The Prabal Garung dress she wore then sold out in an hour after Kate debuted it with William.

One can also be sure that, in addition to the tiara and evening gown, Duchess Kate will surely be adorned with some type of fabulous necklace and earrings. At the Metropolitan Museum of Art gala in New York City last year, she complemented her gorgeous Jenny Packham gown with emerald chandelier earrings.