The Prince pulled out of the memorial for his godfather King Constantine following the news.

How Prince William 'found out' about Kate’s cancer diagnosis before pulling out of Windsor Castle memorial service

Well-wishes have poured in from all over the world for Princess Kate.

Well-wishes pour in for Princess Kate as world reacts to her shock cancer diagnosis

Kate has revealed she is undergoing treatment for cancer.

Kate's cancer: When was the princess diagnosed and what happens next?

Princess Kate has said reassuring her children she is going to be ok is her priority.

Kate says main focus is ‘reassuring children mummy will be ok’ as she undergoes cancer treatment

Kate has been receiving cancer treatment

Watch: Princess Kate reveals she is undergoing treatment for cancer

Kate has announced she is being treated for cancer

Read it in full: Princess Kate speech announcing treatment for cancer

Kate is receiving treatment for cancer

'I'm going to be ok': Princess Kate reassures nation after revealing she has cancer and is undergoing chemotherapy

Queen Camilla gives update on King Charles health during a visit to Northern Ireland

King Charles is "doing very well", Queen Camilla gives health update to well-wishers on Northern Ireland visit

The Princess of Wales with families as she promotes her Shaping Us campaign on early childhood

Princess Kate focusing on her 'lifetime project' as she works from home amid hopes for Easter royal return

Kate underwent treatment at the London Clinic earlier this year

Kate's private hospital 'under investigation for delaying report' of staff 'trying to look at her medical records'

Kate Middleton has reportedly been made aware of the alleged hospital breach

King Charles’ medical records not accessed during ‘data breach’ of Princess Kate’s notes at the London Clinic

Prince Louis can be 'quite a handful', Queen Camilla has joked

Prince Louis is 'quite a handful', Queen Camilla jokes as she continues to step in for King amid cancer treatment

Kate Middleton has reportedly been made aware of the alleged hospital breach

Three London Clinic staff members under investigation over 'attempts to access Princess Kate's medical records'

Downing Street has urged the public to 'get behind the Princess of Wales'.

Leave Kate alone: Downing Street urges public to 'get behind Princess' as she recovers from abdominal surgery

Kate Middleton has reportedly been made aware of the alleged hospital breach

Boss of hospital where Princess Kate was treated speaks out on medical records breach claims

The ICO has launched an urgent probe into the alleged security breach

Kate ‘told hospital staff tried to view her medical records’ as calls for police to investigate ‘major security breach’

Hospital staff 'attempted to view' Princess of Wales' private medical records following abdominal surgery

Police 'looking at' allegations hospital staff 'tried to access Princess of Wales' medical files', minister tells LBC

Archie's christening photo

Picture of christening of Harry and Meghan's son Archie becomes third royal photo flagged as 'edited' by agency