The daschund-corgi cross died a few weeks ago at Windsor Castle during lockdown, several royal correspondents are reporting.
It is not yet established how old he was or what he died of, but he is believed to have been buried at the royal residence. But Buckingham Palace has yet to confirm the news.
It means the monarch has just one remaining pet, another dorgi named Candy.
The news comes after the Duke and Duchess of Cambridge announced the death of their English Cocker Spaniel, Lupo, in a sombre Instagram post just last month.
“Very sadly last weekend our dear dog, Lupo, passed away. He has been at the heart of our family for the past nine years and we will miss him so much,” Will and Kate wrote, signing off with “W & C.”
The Queen has been fond of corgis since she was a small child, and has owned more than 30 of them since her reign.
It was reported in 2015 that the Queen stopped breeding corgis so she would not leave any behind. She has owned four dorgis including Vulcan.