The next 10 performances of the show have had to be cancelled, up to and including the 7.30pm show on Tuesday, July 27.
A spokesperson for the Stephen Joseph Theatre said: "We’d like to reassure you that the person who has tested positive has not come into direct contact with any members of the public inside our building, and any members of our team that they have come into contact with are also isolating."
The box office will be in contact with ticket holders for one of the cancelled shows to organise a new date, refund, or credit.
The spokesperson continued: "We’d be grateful if you could wait for our box office to contact you rather than calling them if possible – they’re going to have to make many phone calls and emails over the next few days, and the faster they can do that, the sooner they’ll get to you."
Bookings will be dealt with through the shows' date order, meaning later bookings may take a few days before you are contacted.
Covid measures remain in place with other areas of the theatre, including the cinema and Eat Me Café, operating as normal.