Princess Diana‘s biographer Andrew Morton was rushed to the hospital Tuesday after collapsing during a book reading. He has since confirmed that he had a “mini-stroke” on Twitter, but is “doing well & on the mend.”
“Andrew was taken ill this afternoon and is currently in hospital as a precautionary measure. We don’t have any further information at this time,” a spokesperson for Michael O’Mara Books, Morton’s book publisher, said in a statement.
Morton told the crowd during his talk in London: “I’m sorry I can’t go on,” before he collapsed into his chair. Morton then left the stage and was sent to the hospital, according to The Sun.
“He forgot what he was saying, was sweating and started to sway,” a source who was present told the outlet. Morton was also forced to cancel a planned event at a London bookstore later that evening, according to the store’s Twitter account.
Morton himself took to Twitter on Tuesday to thank well-wishers for their kind words.
“Thank you for all of your good wishes — seems that I had a mini stroke, but am doing well & on the mend,” he tweeted.
Morton secretly interviewed Diana (through recorded tapes delivered by an intermediary) for his infamous book Diana: Her True Story, which was published in 1992 — the year she separated from Prince Charles. At the time of the book’s original publication, no one knew that Diana herself had provided the book’s source material. That remained a secret until after her death in 1997. After she died, Morton revealed his source to the public.
Since then, he’s published several biographies on other famous figures, including royals such as Wallis Simpson (the book he was promoting when he collapsed) and Prince William, as well as celebrities like Tom Cruise and Monica Lewinsky. His latest book is a biography of Meghan Markle titled Meghan: A Hollywood Princess.
Ahead of the publication of Meghan: A Hollywood Princess, Morton spoke to PEOPLE about Meghan and Harry and how life in the royal spotlight has been difficult for Harry over the years.
“Being a royal has been a romantic curse for him,” Morton said.