The lights will be dimmed across the West End for Maggie Smith next week.
Smith was nominated for an Olivier Award six times, winning the 2010 Special Award for her contributions to all things London stage.
Hannah Essex, Co-CEO of the Society of London Theatre and UK Theatre, said: “Today the theatre world, and the nation, have lost an icon. Throughout her 71 years on stage and screen, Maggie Smith was a magnificent talent and will be remembered as one of the most significant performers British theatre has ever seen.
“Our deepest condolences are with her family and loved ones, and we are proud to be able to honour her remarkable career in some small way.”
West End theatres will dim their lights for two minutes at 7pm on Tuesday 1 October