“Fans arriving at the Royal Opera House in London for tomorrow’s performance of Rossini’s The Barber of Seville are in for a surprise when the curtain goes up. In addition to the expected star cast, headed by the great Peruvian tenor Juan Diego Flórez, they will see an unexpected performance by a star in a cast, after the American mezzo-soprano Joyce DiDonato decided to go ahead with her performance, despite fracturing her leg during Saturday’s first night.”