DAME Helen Mirren "effed and blinded" at a group of drummers playing outside the West End's Gielgud Theatre.
Dressed in full regal costume for her role as Queen Elizabeth II in The Audience, Dame Mirren emerged from the theatre during the performance to ask the drummers to quieten down.
The drummers, who were promoting LGBT festival As One in the Park, said the actress was dressed in pearls and a tiara when she demanded the noise to stop.
A statement from the festival read: "Clearly angered she shrieked 'Quiet! I'm trying to do a play in here! People have paid a lot of money for tickets'."
Rufus Wright, who plays Prime Minister David Cameron in the production, also told the musicians to be quiet.
On Twitter he wrote: "Just fulfilled a lifelong ambition by bellowing at 25 drummers to shut the f*** up. West End theatres got thin walls."
He added: "You should have seen Helen. She came out in full Queen costume and shouted at the drummers too. Honestly. It was breathtaking".
The 67-year-old actress, who won an Olivier Award last week for her performance in the play, told The Telegraph: "I'm afraid there were a few 'thespian' words used. They got a very stern royal ticking off but I have to say they were very sweet and they stopped immediately.
"I would love to track them down and invite them to see the play. I felt rotten but on the other hand they were destroying our performance so something had to be done…Paul Ritter and I could hardly hear each other speak and the audience couldn't hear us at all."
The parade, which had paused outside a bar on Rupert Street for a drum crescendo, were quiet after their telling off from Dame Mirren.
Mark McKenzie, who organised the parade, said: "She was effing and blinding, it was quite bizarre. I said: 'Let's end this now because we can't better that'.
"Not much shocks you on the gay scene. But seeing Helen Mirren dressed as the Queen cussing and swearing and making you stop your parade - that's a new one."
Dame Mirren's spokesman and the Gielgud theatre did not respond to requests for comment.
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