Kate Middleton broke royal protocol by hugging her former history teacher, Jim Embury.

The reunion occurred during her visit to Cornwall on Thursday.

Embury is now a volunteer at the National Maritime Museum in Falmouth.

Embury taught Middleton at St Andrew’s prep school in Pangbourne, Berks in the 1990s.

Middleton was overjoyed to see her former teacher and cried "oh my goodness" before hugging him.

Hugging fans during engagements is generally against unwritten royal rules.

Royals are increasingly breaching this norm to interact with the public.

Last year, Middleton also broke the "no selfie" directive during a trip to Scotland.

Royals are not supposed to take photos with members of the public, but Middleton happily agreed to take a selfie with a fan.