Kate, 42, the wife of heir to the British throne Prince William, had spent around two weeks in recovery at the London Clinic hospital after undergoing surgery for a non-specified, but non-cancerous, condition.

King Charles is thought to still be in the same hospital after he had planned treatment there on Friday to address an enlarged prostate.

Kensington Palace said Kate was now back at home in Windsor.

"She is making good progress," the statement said.

"The Prince and Princess wish to say a huge thank you to the entire team at the London Clinic, especially the dedicated nursing staff, for the care they have provided."

(Reporting by Sarah Young; editing by William James)