Maria Callas was a superstar before the word existed. Unfortunately, her success came at a huge personal cost, and that’s the sad theme at the core of this documentary, which is drawn directly from her letters, TV interviews (especially one with David Frost), home movies and unpublished memoirs.

Born in New York City, but stuck in Greece during WWII, Callas owed her singing career –but also her deep regrets – to an extremely pushy mother and later an equally domineering husband.

She made no bones about the fact that she would gladly have swapped her vocation for the joys of motherhood and a happy private life. She was also deeply traumatised by the fickleness and cruelty of some of the media, who ‘lynched’ her over her failure to complete a concert performance in Milan. (Never mind that the poor woman had bronchitis!) And then there was her long and complicated relationship with Aristotle Onassis, who of course eventually married Jackie Kennedy.

Maria By Callas is unquestionably well made, and was exhaustively and meticulously researched. Some of the footage is fascinating, notably the brief scenes from the making of Pasolini’s Medea, in which she starred and acted. The catch is that the doco – being so subjective – is not quite satisfying in terms of giving a fully-rounded portrait of its subject, and we’re not always entirely sure what to take at face value. On the plus side, given her technically phenomenal voice, the footage of her singing will be thrilling to people who aren’t impervious to the charms of opera.