She said at the time: "My father fought all of his life to put his dynasty back on the throne."
Maria Teresa never had kids and is survived by her six siblings, Francoise, Cecilie, Marie des Neiges and Prince Sixte Enrique as well as six nieces and nephews.
The news comes after Princes Charles announced he tested positive for the virus on Tuesday.
The Prince of Wales took to Instagram on Tuesday to thank fans for their support.
“Thank you for all your ‘Get Well Soon’ messages for His Royal Highness. He is enormously touched by your kind words,” the statement read.
Prince Charles has shared his first message with fans, since testing positive for coronavirus.
Charles is currently self-isolating at his Scottish home Birkhall, in Aberdeenshire, with Camilla living separately in self-isolation in another part of the estate.
Despite the shock news, Camilla Parker Bowles is said to be in “good spirits” following the Charles’ shock coronavirus diagnosis on Wednesday.
While the palace is yet to provide an update on Charles’ health, a spokesperson reportedly said the Duchess is remaining “upbeat” given the seriousness of the news, People reported.