Judi Dench, Ian McKellen and Maggie Smith are among some of the biggest names in British theatre who will join forces for a one-off Zoom performance in aid of the struggling arts industry. Derek Jacobi and Kenneth Branagh will also take part in the performance, which will raise money for people who used to work in UK theatres closed by the pandemic. “We can’t appear on the stage and we can’t be in a studio … but we can be on this extraordinary thing called Zoom,” Dame Judi told the BBC’s Andrew Marr Show. None of the cast will be told much about what they will be doing in advance of the show, she said, describing it as “an actor’s nightmare”. The proceeds will go to the charity Acting for Others, of Dench is president, to provide emotional and financial support to onstage, backstage and front-of-house workers. “It does go to the people who are all self-employed and don’t necessarily act, but work in the theatre and keep the theatres going,” she said. Asked if the government’s £250m emergency funding for arts venues, museums and cultural organisations would save the sector, she said: “We naturally want more, but then so does everybody. But [theatre] does bring a huge revenue to this country.” The comedy performance, called For One Knight Only, will take place on 29 November and tickets cost £45. The event, produced by the Red Dwarf co-creator Rob Grant, The Young Ones director Paul Jackson and the actor and producer Richard Clifford, will feature a live Q&A with the cast throughout. Dench said people had relied on TV and films for entertainment during lockdowns, but that theatre, which is the training ground for many actors, was in a desperate situation. “All those young people who are coming out of drama school and wanting to start jobs, and being eager about it. They can’t do anything,” she said. “We need to help them and we need to encourage them, and we need to keep the flame going.” The seven-time Oscar nominee made her acting debut in 1957 at the Old Vic and established herself as one of the most significant British thespians before rising to international fame with blockbuster film roles, including as M in the James Bond series.