Kate Middleton is self-isolating after she came into contact with someone who tested positive for COVID-19, Kensington Palace announced on Monday.

A spokesperson said the Duchess of Cambridge "came into contact" with the unnamed individual last week. Thankfully, she is "not experiencing any symptoms, but is following all relevant government guidelines." She is said to be self-isolating at home.

The 39-year-old royal was forced to miss out on the event honouring the 73rd anniversary of Britain's National Health Service. She had planned to join her husband, Prince William, at St. Paul's Cathedral on Monday. The Duke of Cambridge reportedly does not need to self-isolate so he went to the event solo.

It is unclear when exactly last week Kate Middleton came into contact with the COVID-19 positive individual. She attended several events during this time, and was prominently at Wimbledon on Friday, where she is Patron of the All England Lawn Tennis Club.

Inside the #Wimbledon Lawn Tennis Museum, opened by The Duke of Kent in 1977 pic.twitter.com/g2leYdqqiL

— The Duke and Duchess of Cambridge (@KensingtonRoyal) July 2, 2021

The mum-of-three also joined Prince William and their son Prince George to watch the Euro 2020 football match between England and Germany on Tuesday. She reportedly took lateral flow tests prior to her engagements at the Euros and at Wimbledon, and both came back negative. She also gets tested twice weekly as mandated by the Royal Household testing regime.

According to Today, Kate Middleton could be in quarantine for up to nine more days depending on when her self-isolation began. There is also no word if she has been tested for the virus following the exposure with the COVID-19 positive individual. It is a known fact though that she has already been vaccinated against COVID-19.

She got her first dose at London's Science Museum late in May. She shared a photo taken when she had the jab on the official Twitter page of The Duke and Duchess of Cambridge. It is not known though if she already had her second dose of the vaccine.

Yesterday I received my first dose of the COVID-19 vaccine at London’s Science Museum. I’m hugely grateful to everyone who is playing a part in the rollout - thank you for everything you are doing. pic.twitter.com/h427iT0n4x

— The Duke and Duchess of Cambridge (@KensingtonRoyal) May 29, 2021

Kate Middleton has not been reported to have contracted COVID-19 unlike Prince William, who "struggled to breathe" when he got the virus in April. Prince Charles also got the disease at about the same time as his son. He had milder symptoms though but lost his sense of taste and smell.

Prince William, Kate Middleton and their children
The Duke and Duchess of Cambridge, Prince William and Kate Middleton, with their children Princes Louis and George and Princess Charlotte. Comic Relief/BBC Children in Need/Comic Relief via Getty Images Comic Relief/BBC Children in Need/Comic Relief via Getty Images