Jennifer Caldwell, who was working in the box office in London’s Arts Theatre, got the call to fill in when the understudy was already filling in someone else’s role: “One of the producers saw me on the box office and said ‘I’ve had an idea’ about getting me to fill in. I said maybe, so he said ‘what if we cut parts of the show – can you do a reduced version of the track?’ and I said why not! We rehearsed from 3.30pm until 5pm and were on stage at 7pm.”