Talking to Edith Bowman on Yahoo Movies, Blessed said: "The Queen, it's her favourite film, she watches it with her grandchildren every Christmas."
The 83-year-old then impersonated Her Majesty's voice in the interview, saying: "You know, we watch Flash Gordon all the time, me and the grandchildren. And if you don't mind, I've got the grandchildren here, would you mind saying 'Gordon's alive'?"
He added: "Everywhere I go, they all want me to say 'Gordon's alive!'. The butcher, the baker, the candlestick maker, horses and queens, and prime ministers, they all want me to say, 'Gordon's alive!', it's their favourite film."
Blessed's interview in which he made the hard-to-credit claim about the Queen was part of a promotional tour for the 40th anniversary reissue of the film.
He did not detail how or when he learned about her supposed love of Flash Gordon.
The actor, who has also starred in Z-Cars, I Claudius and The Black Adder, met the monarch in 2016, when he was awarded an OBE for services to the arts and charity.
Brian Blessed poses after he was made an Officer of the Order of the British Empire (OBE) by Queen Elizabeth II. Photo / Getty Images
Off-screen, Blessed has tried to climb Everest, undergone Russian space training and claims to have sparred with the Dalai Lama.
Interviews with him are rarely short of extraordinary revelations – he has described how he helped deliver a baby in a park and enjoyed a close relationship with Agatha Christie despite a 46-year age gap.
The Queen's favourite film was previously said – by its writer Willy Russell – to be Shirley Valentine.
The 1989 romcom stars Pauline Collins as a Liverpool housewife who falls in love with Greek tavern owner Tom Conti.
