The famously tempestuous Romanian soprano is, we learn, living a separate life from her husband Roberto Alagna. If Opera's Most Romantic Couple is no more, will Brand Angela be terminally damaged? Surely a showcase performance in the South Bank's International Voices season would be just the thing to rally the faithful and reaffirm Ms Gheorghiu's spectacular star quality, but I must admit that by the time we reached the interval, I was beset with gnawing doubt.

It finally came just over three hours in. Ferruccio Furlanetto’s gouty Philip II leans his elbow on his chair and begins to grind his head into his right-hand like he's a human pestle and mortar. He first castigates himself for ever having thought that his wife, Elizabeth of Valois - who he suspects of sleeping with his son, Don Carlos - might have fancied his unyielding, aged presence, and then tries to sing his way out of his tortured predicament.