Mr Sondheim and Bryn Terfel’s bin

Emma Thompson makes her New York stage debut playing Mrs Lovett opposite Bryn Terfel, when the Welsh bass-baritone sings the title role in a special production of Stephen Sondheim’s Sweeney Todd with the New York Philharmonic next week.

But Sondheim did not give Terfel much opportunity to digest his notes when the master songwriter paid him a visit to discuss the role. “He came in to my dressing room in Chicago and I was filled with dread about what he was going to say,” Terfel tells me. “Everything he said made terrific sense. He wrote out his notes but then he just chucked them into the bin. My eyebrows shot to the ceiling. Once he left the room I unscrunched them and stuck them in my score. I’ve got Sondheim’s scribbles now.”