When Metropolitan Opera supremo Rudolf Bing found Helen Traubel, his star Wagner soprano of the early 1950s, slumming it off-Broadway with showtune gigs, he fired her on the spot. His current successor Peter Gelb would most likely applaud this latest of one of his star soprano’s crossover projects: a full-on evening of Porter, Rodgers, Arlen, Kern, Jobim et al, most carefully prepared and (says Mattila in the booklet-note) “like studying a new and stylistically completely different opera role”.To cross over from opera to showtime into another language, and, let’s face it, culture, is a huge achievement (Traubel was at least born in Saint Louis, not in Somero). But can Mattila be funky with a jazz ensemble instead of a Strauss or Janácek orchestra behind her? Assembled from several shows, her performances here grow in confidence from the rather stilted English of “It’s all right with me” via a genuine (rather than quoted) sexual huskiness in “Fever” to a real trouper’s use of musical space and time in “The Man I Love” and the (oddly downbeat) closing number “Come rain or come shine”. Along the way, she has a good go at scat singing and in delivering climactic phrases that swing rather than hold the air like operatic high notes, but blues numbers come over more studied than felt.

Lintinen’s arrangements are ultra-busy orchestrations around Mattila’s voice where every sung line is assigned a separate obbligato instrument or texture. It’s well rehearsed (as are the in-your-face backing trio How Many Sisters), and closely but naturally recorded, but it doesn’t always swing. A pity that instant recording of new “star” projects is so easy and de rigueur; there’ll be looser, funkier, real-er showboating albums from this soprano to come.