ET has learned that Markle was in London when Prince Harry went to Scotland.
Meghan Markle was in London Thursday when Queen Elizabeth II died, ET has learned. While Markle was not by her husband's side at Balmoral Castle in Scotland, both she and Prince Harry paid tribute to the Queen via their Archewell Foundation.
Setting the foundation's website to all-black, Harry and Meghan devoted the front page of the site completely to the Queen with a message in white that reads, "In loving memory of Her Majesty Queen Elizabeth II." Underneath were the Queen's birth and death year, marking her 96 years of life, from 1926 until her passing in 2022.
New speculation about the queen's health began in earnest when members of the royal family traveled to Balmoral Castle in Scotland on Thursday to be by the royal matriarch's side as doctors expressed concern for the 96-year-old British monarch's health.
Prince Harry, Prince William, and their father, Prince Charles, all made the trip to be by the queen's side, while Meghan remained in London -- though royal reporters noted that she would not attend the previously planned WellChild Awards, part of the Duke and Duchess of Sussex's trip abroad.
"It's understood that the family wanted Prince Harry to be there, even though he was unable to get to Balmoral in time to see his grandmother, but Meghan, the Duchess of Sussex, was not, we understand, invited to join the family," royal expert Katie Nicholl told ET. "She has said she will go to Balmoral another time, but I think it is quite significant that Prince Harry traveled to Balmoral on his own without his wife."
Later that day, Buckingham Palace announced that Queen Elizabeth II -- the United Kingdom's longest-reigning monarch -- had passed at the age of 96.
"The Queen died peacefully at Balmoral this afternoon," the palace's statement read. "The King and The Queen Consort will remain at Balmoral this evening and will return to London tomorrow."
Kate Middleton was not in attendance at Balmoral either. The soon-to-be Princess of Wales stayed home to be with her and William's three children -- Prince George, 9, Princess Charlotte, 7, and Prince Louis, 4 -- as Thursday marked their first day of school at Lambrook School.
Elizabeth's other children, including Princess Anne, Prince Andrew, and Prince Edward, also made the trip to Scotland, as did Camilla, the Duchess of Cornwall, and Sophie, the Countess of Wessex.
For updates on Queen Elizabeth's death, visit ET's ongoing coverage and see more below.