The Princess consort has been married to Hans-Adam II the current Prince of Liechtenstein since 1967.
An official statement said: “The Princely House regrets to announce that HSH the Princess suffered a stroke yesterday.
“She is receiving care in the hospital.
“The Princely Family asks for your understanding that no further information will be given at this time.”
On Twitter, fans of the royals wished the Princess consort a speedy recovery.
“Hopefully she makes a good recovery,” one user said.
Another added: “Here's wishing her a full recovery.
“My thoughts and prayers are with the family.”
Marie and Hans-Adam II, who became engaged in 1965, have four children together and fifteen grandchildren.
Marie was born on 14 April, 1940 in the Czech Republic.
Her husband, the Prince of Liechtenstei,n was born in 1945 and has reigned since 1989.
He remains head of state but passed the day-to-day running of Liechtenstein to his son, Crown Prince Alois, in 2004.
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Although Liechtenstein only has a total population of only 38,378 [as of 2019], their Royal family is the second richest in Europe - owning a bank, extensive investments and a 400-year-old art collection.
Liechtenstein women do not inherit the throne meaning Tatjana Marie’s daughter is not in the line of succession.
In the British royal family, male siblings were able to jump ahead of older sisters in succession until the Queen passed the Succession of the Crown Act in 2013.
This was introduced in 2015 when Princess Charlotte was born.
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Thus, Prince Louis is behind Princess Charlotte in the path towards the throne.