Sir Ian McKellen is facing calls to hand back his knighthood

Royal biographer Margaret Holder has now told the Daily Express about his remarks - which he made during a chat with The Times: "Perhaps if Sir Ian feels so slighted by the Queen he could consider returning his knighthood, although he may regret that in the future."

Margaret also referred to the actor's fall from stage in June in London, which left him hospitalised, adding: "We have to remember this is an elderly man who had a nasty accident recently. Perhaps he may say something different in time to come."

Dickie Arbiter, the late Queen's official spokesman between 1988 and 2000, also hit out at the actor for making his comments after accepting an honour from the Queen.

He said: "Ian McKellen was being somewhat churlish and over the top suggesting the late Queen was rude when she asked if people 'were still going to the theatre'.

"Theatres have complained for years about high costs and a lack of bums on seats - a perfectly legitimate question. If that's how he felt, why accept the honour?

"It was a snide attack not expected of an intelligent man with such stature. The question is, 'Did the late Queen really say that?' and, if so, why come out with it now? A cheap shot."

Sir Ian was knighted for services to the performing arts in 1991 and Queen Elizabeth II appointed him Companion of Honour for his services to drama and equality in 2008.

He said about the Queen: "I'm sure she was quite mad at the end. And on the few occasions I met her she was quite rude.

"When I received a medal for acting, she said, 'You've been doing this for an awfully long time'.

"I said, 'Well, not as long as you'. I got a royal smile for that, but then she said, 'Does anyone still actually go to the theatre?'

"That's bloody rude when you're giving someone a medal for acting.

"It meant, 'Does anyone care a f*** about you because I don't. Now off you go!'"

Ian added about the Queen's late husband Prince Philip he was "deeply, deeply eccentric" possibly "deeply unhappy".

He said: "Same with the present king. He sort of survives, but he is clearly damaged.

"As for (Prince) Harry, he's probably not bright enough or doesn't have the right friends to really help himself."