Princess Kate didn't curtsy to King Charles at the Commonwealth Day Service in London on March 13.

Every member of the Royal Family is expected to curtsy to the King and Queen consort, but only once a day.

Kate's lack of gesture towards her father-in-law means she presumably hung out with him earlier that day.

TikTok has sparked an interest in the Princess of Wales curtsying and/or being curtsied to lately.

Commonwealth Day is the official day designated for celebrating the Commonwealth of Nations and all its member countries.

A service is held at Westminster Abbey, with senior royals in attendance.

The Princess of Wales wore an elegant ensemble by Erdem consisting of a peplum jacket and matching skirt.

She paired the look with navy pointed pumps, an embellished navy hat, and a Prince of Wales feathers brooch.

The brooch was given to her by the King.