- Babykins: When Prince William's phone was hacked in 2006, his private messages revealed that he referred to Kate as "babykins" and "baby."
- Darling: In 2016, William and Kate were overheard calling each other "darling" at the Chelsea Flower Show.
- Poppet: William has also been heard calling Kate "poppet" multiple times.
- Squeak: During a visit to St. Andrews in 2012, Kate revealed that her classmates used to call her "Squeak" after the school's guinea pig. "There was one called Pip and one called Squeak, so my sister [Pippa Middleton] was called Pip and I was Squeak."
- Princess-in-waiting: Kate was given the moniker by her friends during her time at Marlborough College because she reportedly had a photo of William on her wall.