Almost everything about this disc is inevitable. A real-life couple, Ailyn Pérez and Stephen Costello share much of the same repertoire, their significant points of musical compatibility (mid-weight lyric singers able with coloratura technique) being highlighted by their distinct personalities. She’s a warm-hearted, latter-day Victoria de los Angeles from Chicago and he’s from the rockier terrains of blue-collar Philadelphia with an increasing vocal resemblance to the young Alfredo Kraus.

Why didn’t they make this disc years ago? For all their earlier successes – both made their Salzburg Festival debuts in 2008 – Costello needed to get his tonsils out of the way with 2011 surgery before his voice could truly bloom. She had to conquer her pitch variability in high-wire lyric soprano roles such as Violetta (which she now sings with more solid technique than almost anybody out there). So this disc’s time has come, and it’s a warm bath. No problems. Much pleasure. And thrills – plus solidity, with Patrick Summers conducting the BBC Symphony Orchestra.

They’re basically Italianate singers, with rounded phrases whose resolutions are delayed with that extra, emotionally infused nanosecond rendered so convincingly that one isn’t going to begrudge them taking a less-than-Gallic approach in the Act 2 duet from Manon (so many others do the same). And later on, their more cultivated French style in Faust is the best grand-opera performance on the disc. The Cherry Duet from L’amico Fritz is phrased far more stylishly than it needs to be. Maybe the comedy in L’elisir d’amore is a tad heavy-handed. Like even the most seasoned bohemians, their climactic note in ‘O soave fanciulla’ feels a bit squeezed. But with minimal shift in vocal technique, they sing Broadway with much self-possession and excellent English – not always the case with American singers by any means. Basically irresistible.