Prince Andrew‘s ex-wife, Sarah Ferguson, has paid tribute to Queen Elizabeth II following her death on Thursday. The Duchess of York took to Twitter to praise her late mother-in-law for her immense impact on the UK and Commonwealth and honour their personal relationship as well.

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“She has given her whole life selflessly to the people of the UK & the Commonwealth,” Ferguson penned. “To me, she was the most incredible mother-in-law and friend. I will always be grateful to her for the generosity she showed me in remaining close to me even after my divorce.”

In a follow-up tweet, the royal revealed, “I will miss her more than words can express.”

Ferguson married Prince Andrew, the Queen’s second eldest son, in 1986, however, the Duke and Duchess of York, split up in 1992. Despite their divorce, they have remained friends and Ferguson has remained a close member of the royal family.

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The former royal couple share two daughters, Princess Beatrice and Princess Eugenie, who are among the Queen’s eight grandchildren.

In August, ET caught up with Ferguson to talk about her new novel, Her Heart for a Compasswhich she explained was inspired by her real-life story of marrying into the royal family.

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“I think at 61 I have a much better understanding of the strength of my own voice — and that’s really pretty exciting,” she told ET’s Kevin Frazier at the time. “It’s taken me a long time to get to this voice which I’m really pleased about.”

For updates on Queen Elizabeth’s death, visit ET’s ongoing coverage here.

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