King Charles's coronation is scheduled for May 6 at Westminster Abbey.

The tiara that Kate Middleton will wear on the day is still unknown.

Camilla will be wearing Queen Mary's Crown.

Kate has rotated between three historic headpieces 13 times since marrying into the royal family.

The Cartier Halo Tiara was the first tiara Kate ever wore, and she has worn it 13 times.

The Lotus Flower Tiara and Lover's Knot Tiara are also favorites of Kate.

Kate may also wear a coronet, which is a small crown often worn at a coronation.

Princess Diana's favorite tiara, the Lover's Knot Tiara, is one of Kate's go-to pieces.

Kate may wear the Grand Duchess Vladimir Tiara or the Girls of Great Britain and Ireland Tiara.