Last month at Baby Jupiter, Danielle Brancaccio took the stage carrying a hip flask. “It’s just for effect,” a friend confided, but those shots she was taking looked pretty damn authentic. Indeed, the Professor and Maryann singer’s voice does have a certain liquor-soaked, after-hours quality to it at times, and when she moaned, “There’s no milk in the icebox/All my hopes wash out to sea” during “Lonesome Old World,” the opening track on the acoustic pop duo’s latest, self-titled album (Bar/None), she sounded like she deserved every last drop.

Brancaccio’s partner, singer-songwriter-guitarist Ken Rockwood, on the other hand, looks like he’s never had a drink in his life. Bespectacled, balding, and resembling a younger Ben Stein, Rockwood could have walked into the bar after a long day teaching high school algebra. The quiet creative force behind P&M left vocal duties exclusively to his diva, and concentrated on coaxing simple, moving melodies from his acoustic guitar. Between songs, as Brancaccio chattered to the audience about her bad hair day (“I look like David Cassidy!”), Rockwood lovingly wiped clean his instrument with a handkerchief.

Yes, they are an odd couple, but the fact that they make the kind of music they make is even odder. Something about Brancaccio’s demeanor gave the impression that she wanted to rock out a bit more than P&M’s powerful yet soft repertoire allowed. Maybe it was her low-cut, bright-red tank top; maybe it was her foul mouth (which she apologized for); maybe it was the hip flask. Maybe it was the one glorious yell on “Not You Not Me” that stopped dramatically short. Similarly, Rockwood’s intensity wouldn’t seem out of place in a prog-rock ensemble.

Regardless, it works. The couple share an uncommon intimacy onstage, rarely looking at each other yet moving their bodies in such a way that they appear to be conscious of each other’s every breath. Musically, they are perfectly matched, able to walk among the clouds on the dreamy “Electric Lights” and crawl around in the shadows on the spooky “Is That You.” The guitar and voice took turns leading and following, chasing and being chased, dancing together and sometimes becoming one. With closed eyes, at times it would have been difficult to believe that two different people stood on that stage.