Stephanie Nakasian and Hod O'Brien

When Northwestern MBA and Wall Streeter Stephanie Nakasian met jazz pianist Hod O'Brien almost 30 years ago, a marriage-included collaboration was almost instantly formed, one that they continued to augment only a few days back at the Metropolitan Room.

And here I need to digress somewhat to explain that the Metropolitan Room becomes a jazz venue quite often these days, particularly in the later hours. (I've only just learned that management in the hot boite doesn't necessarily consider the late show prime time.) The music genre shift isn't, of course, unusual nowadays, because jazz and pop have overlapped the last few decades in ways they rarely did during the middle of the 20th century.

As a matter of rewarding fact, they overlapped considerably when the unusually warm Nakasian glided into a number. Oh yes, she stood true to her roots by scatting whenever she sensed a welcome opportunity, but when she delivered "East of the Sun (and West of the Moon)" (Brooks Bowman), she was anything but reluctant to display the emotion behind the words as well as the melody's silkiness. She also recognized humor in lyrics, as she did with Dave Frishberg's "You Would Rather Have the Blues."

But jazz scat-cat that she is, she moved the likes of Cole Porter's "Why Shouldn't I?" around with verve — "I love improvisation," she trumpeted at one point, when consulting her song list and then reshuffling it on the spot. And speaking of trumpets, she was even more adventurous on "Perdido" (Juan Tizol-Ervin Drake-H.J. Lengsfelder). Up until then, Nakasian had been holding the mike so that she only seemed to be fingering a trumpet. During a break from the "Perdido" lyric, however, she launched into a rasping trumpet imitation that could have fooled Miles Davis.

It may be no wild guess that this Nakasian gift is one of the things that won her instrumentalist O'Brien's heart. And his chunky but never clunky playing has to be a continuing aphrodisiac for her too. Intent over the keyboard, he did his energetic thing on most of the inclusions.

Not incidentally, Nakasian will sing a standard or two or three in the course of a set, but she wants to shake them up, as she did astonishingly with "Night and Day" (Porter again) against jungle rhythms in the drums. She also takes pleasure splicing the evergreens with rarely done gems such as "Maybe September" (Ray Evans-Jay Livingston-Percy Faith). The balance between the familiar and the not-so is just about right.

Presented by and at the Metropolitan Room, 34 W. 22nd St., NYC. Aug. 15 and 16.