A cast member at the Royal Opera House has unfurled a Palestinian flag on stage during the curtain call on Saturday night.
Video shows a brief scuffle as an official at the London venue tries unsuccessfully to stop the protest, with the performer refusing to let go of the large flag.
It came on the closing night of Il trovatore, a four-act opera by Giuseppe Verdi.
Royal Ballet and Opera said the protest was “completely inappropriate for a curtain call”.
A spokesperson said: “The display of the flag was spontaneous and unauthorised action by the artist.
“It was not approved by the Royal Ballet and Opera and is not in line with our commitment to political impartiality.”
Palestinian flags are commonly seen at protests held in support of Gaza as the Israel-Gaza war continues.
One cast member standing at the top of the stage is seen in videos of the incident silently displaying a large Palestinian flag, at one point shaking it gently.
While the audience continues to applaud the performance, a man from the stage wings is seen attempting to wrestle the flag away from the cast member but they resist and hold on to it for the remainder of the curtain call.
Two other performers stood alongside the one launching the protest can be seen lurching to their side as the tussle plays out.
Some cast members further forward on the stage appear not to realise what is happening behind them.
Other officials stood in the wings can be seen shouting messages to the protesting cast member, who looks ahead and appears to ignore them.
One member of the audience posted on X: “Extraordinary scenes at the Royal Opera House tonight.
“During the curtain call for Il trovatore one of the background artists came on stage waving a Palestine flag.
“Just stood there, no bowing or shouting. Someone off stage kept trying to take it off him. Incredible.”
The identity of the cast member is unclear.
Il trovatore has now finished its 11-night run at the Royal Opera House, Covent Garden.