The Imperial Theatre in Saint John has received a huge gift.

Following a performance Thursday night, Arthur and Jack Irving handed over a cheque for $500,000 to top up the theatre's capital campaign.

"We received an incredibly generous and very special gift from Arthur Irving and Jack Irving," the theatre's general manager, Peter Smith, said Thursday night.

"It was incredible when I announced the donation. The audience got up on their feet and applauded, and they wouldn't stop. It puts us over the top of our goal, and puts us just over $2.9 million."

The Keep It Live campaign began in June 2008, with a goal of raising $2.5 million.

Smith said that government funding for the theatre is strictly for operations; there's no money for capital improvements. So the theatre had to carry out a fundraising campaign to cover them.

"The most urgent thing was replacing the cladding on the building, which is almost finished. That one project cost almost $1 million, which had to be done right away because it was leaking," Smith said.

"Beyond that, there were a whole bunch of things that needed upgrading and replacing — sound system, lighting system, ticketing system and drapes needed replacing."

As a way of thanking the Irvings for their generous gift, Smith said that for the next 15 years, the Imperial Theatre will rename its auditorium Fort Reliance, the name of one of the family's holding companies.