The Last Night of the Proms could see hundreds of EU flags being waved after an online campaign to show "solidarity" with Europe.
Audience members may be handed the flags at London's Royal Albert Hall on Saturday as the event takes place almost three months after Britain voted to leave the EU.
A crowdfunding page has raised more than £1,100 to buy the flags, with the annual musical event apparently chosen as it is "televised and has a very high profile".
An organiser wrote: "As music is such an international activity that benefits greatly from our membership of the EU this event feels an appropriate venue to show UK solidarity with the EU."
They added: "Concert-goers waving EU flags along with the Union Jack would send a message to the world and our own people about how much music lovers value the EU."
People commenting online described the idea as "brilliant" and "fantastic".
On Thursday, an organiser wrote that the page would be deleted due to "negative publicity" and to protect the privacy of supporters, but added: "Flags have all been bought, watch on FB (Facebook) for what happens on the night."