In her new role as queen consort, Letizia will inherit greater responsibility but also have more access to beautiful crown jewels from her mother-in-law Queen Sofía, which have in turn been passed down through the generations. These are owned by the royal family itself rather than belonging to the Spanish state.
Scroll down for a closer look at the jewels Letizia will be wearing...
"Fleur de Lys" tiara
A wedding present from Felipe's great-grandfather King Alfonso XIII of Borbón to his beloved wife Victoria Eugenia of Battenberg, this stunning headpiece was made in 1906 for the couple's May wedding. Princess Victoria wore the diamond and platinum tiara at the ceremony, proudly showing off the Fleur de Lys design – the House of Borbón's heraldic emblem.
The tiara is the most important piece in the collection, and was first worn by Queen Sofía at a state dinner held in honour of Queen Elizabeth II.
In 1920, French jewellers Cartier designed a bespoke piece of jewellery for Queen Victoria Eugenia, who was also known as Ena. The art deco tiara featured seven large pearls encircled with diamonds. It has only been worn by two queens in the past – Ena and after 1975 Sofía.
Russian pearl necklace
Felipe's great-great-grandfather King Alfonso XII presented his first wife Queen Mercedes with this beautiful necklace made of 41 pearls and a diamond clasp. Originally weighing two kilograms, the necklace had four pearls removed to make it shorter.
"La Chata" tiara
In the 19th century Queen Isabel II commissioned Paris-based jewellers Mellerio to create a piece of jewellery for her daughter Princess Isabel, who was also known by the nickname "La Chata" – meaning snub nosed.
The design was a beautiful reflection of the sea, featuring shells and the movement of the waves.
Queen Sofía was presented the tiara when she married Felipe's father King Juan Carlos in 1962. It was worn by Princess Letizia in 2007 when former president of the Philippines Gloria Macapagal-Arroyo visited Spain.
Necklace made of large mounted stones Queen Victoria Eugenia left various necklaces when she passed away. The largest made of 30 large stones was eventually passed down the line to King Juan Carlos for his wife. It was made by Spanish jewellers Ansorena.
"Queen María Cristina" tiara The jewel belonged to King Alfonso XII's second wife, Queen María Cristina, and was first worn in 1906. The stunning piece is reminiscent of upside-down tear drops, flanked by two rows of 14 diamonds.
Queen Sofía has worn the tiara on three recent occasions – on her official tour to Norway, and when she welcomed the King of Saudi Arabia and the former president of the Philippines on state visits.
"Mellerio floral " tiara
Princess Letizia has identified two tiaras as her favourite, one is the "Mellerio floral" piece. Made by Paris-based jewellers Mellerio, the delicate tiara is made of five flower designs complete with stems and leaves.
This is another favourite with Letizia. The mother-of-two wore this on her wedding day in 2004. The platinum Imperial tiara, made by German jewellers Koch, features Parthenon-style columns, rows of leaves and a central tear drop diamond.
It is one of the most important pieces from Queen Sofía's collection, as it was originally owned by her grandmother, who received it on her wedding day from her father Kaiser Wilhelm II – the last German emperor.
A century after King Alfonso XIII commissioned Ansorena to create the "Fleur de Lys" tiara for his beloved Princess Victoria Eugenia in 1906, the Spanish jewellers decided to make a special jewel for Princess Letizia too. The elegant piece was crafted with 450 diamonds, ten perfectly round Australian pearls and 3,000 gemstones.