The Princess Royal also wore a choker once owned by Queen Mary that hasn’t been seen in decades.

BRITAIN-NIGERIA-ROYALS-DIPLOMACY
No member of the British royal family has made the rewear quite the art form in the way Princess Anne has. Her wardrobe has long included investment pieces dating to the 1970s, and Wednesday’s appearance may mark one of her best throwbacks to date.
Last night, Anne joined King Charles, Queen Camilla, the Prince and Princess of Wales, and the Duke and Duchess of Gloucester to host Nigerian President Bola Tinubu and First Lady Oluremi Tinubu at Windsor Castle. She chose a white gown and cape that she first wore 57 years ago, when she was 18 years old.
State Visit By The President Of The Federal Republic Of Nigeria And Mrs. Tinubu – Day One
Princess Anne walks through St. George’s Hall with her husband, Vice Admiral Sir Timothy Laurence, for the Nigerian state banquet.
Anne first wore the piece—featuring lattice details at the neckline, sleeves, and hem—on June 4, 1969, attending the world premiere of the British drama Run Wild, Run Free.
La Princesse Anne reçoit un bouquet de fleurs
Princess Anne at the movie premiere in 1969, wearing the gown with the same lattice detailing on the sleeves, with a different neckline.
Princess Anne accessorized the gown with a few histoic jewels as well, including Queen Mary’s City of London pearl and diamond choker—which was seen for the first time in decades. Per The Royal Watcher, when Princess May of Teck married the future King George V in 1893, she received numerous jewels as gifts. Among them, May—later known as Queen Mary—received a pair of pearl and diamond bracelets in a lattice design that could be worn together as a choker, which was gifted by the Lord Mayor and the City of London at the time.
Mary of Teck, Victoria Mary Augusta Louise Olga Pauline Claudine Agnes, 1867 – 1953
A portrait of Mary of Teck, dated to 1935. Among the many jewels she is wearing is the City of London choker.
The choker might be more familiar on Queen Mary than Anne as it was a lifelong favorite of the late Queen’s and she wore it in many portraits up until her death in 1953. It was passed down to her granddaughter, Queen Elizabeth. However, Elizabeth rarely wore chokers, so it was eventually passed to Anne. One of the last known appearances of the choker in public was on Anne in at a gala at the Natural History Museum in 2005.
Festival Of Trees – Gala Dinner
For her headpiece, Anne chose a paternal family heirloom inthe Meander Tiara, from Princess Alice of Battenberg (also known as Princess Andrew of Greece). Featuring a diamond-encrusted, Grecian design with a central diamond ringed by laurel leaves, Alice gifted the sparkler to her daughter-in-law, Queen Elizabeth. Anne has been seen wearing the diadem since the 1960s, although one of the tiara’s most famous appearances was in 2011 when it was worn by Anne’s daughter, Zara, on her wedding day to Mike Tindall.