Richard Briers, Linda Nolan and Gemma Redgrave were present
Stars from every West End production were present at Sunday's open-air concert, with Richard Briers, Jemma Redgrave and Paul Nicholas among the biggest names.
The show, which entertained Christmas shoppers in Covent Garden's piazza, was organised by actress Jenny Seagrove.
West End attendances dropped by up to 16% in the weeks immediately following 11 September, but are now reported to be bouncing back.
The concert also included songs from musicals and was intended to persuade shoppers and tourists that they should return to the stalls.
Funds raised by the event will be donated to the Red Cross.
A number of successful new shows have helped lessen the impact of reluctant audiences, while families are expected to give theatre coffers another boost during the forthcoming school holidays.
London's mayor Ken Livingstone recently provided a £500,000 subsidy for tickets so that audiences could be tempted with cheaper prices.
And Prime Minister Tony Blair recently made a high-profile visit to watch a production of Noel Coward's Private Lives at the Albery Theatre.
Major blow
Four West End shows all announced plans to close soon after 11 September, and there were fears that cast and crew members would lose their jobs or be forced to take pay cuts.
Audience numbers were down 15.2% in the week after 11 September, according to The Stage newspaper, while they were down 16.4% in the following week.
One major blow for theatres has been the fall in foreign tourists, who account for a significant part of revenue.
In October, 31% less visitors entered the country compared with last year.