‘The Roommate’ Pairs Patti LuPone and Mia Farrow on Broadway

“Sweet and sour?” Patti LuPone suggested, as if considering options on a menu. She looked questioningly at Mia Farrow, who was sitting next to her in a small atelier in a Midtown Manhattan hotel. We were in the heat-soaked throes of early August, and the women had just arrived, depleted, from what they described as an “airless” rehearsal room nearby.

“I don’t know,” LuPone said. “It’s kind of negative, the sour …” She hesitated. “SALTY!,” she then exclaimed, in the clarion voice that has resonated from so many stages over the past five decades. “Sweet and salty.”

LuPone was trying to define the yin and yang of the most unexpected double act of the new Broadway season. Farrow (she would be the sweet) and LuPone (salty) are the stars and entire cast of Jen Silverman’s “The Roommate,” which is in previews and opens on Sept. 12 at the Booth Theater, under the direction of Jack O’Brien.

They portray women of radically dissimilar backgrounds and temperaments, who come into intimate and potentially combustible contact. These are roles for which Farrow and LuPone, longtime friends who have homes in the same Connecticut county, would seem to be naturals. “We complement each other, because we are so different,” LuPone said.

Farrow, whose habitual manner melds openness with wariness, said: “I don’t know if at the core we’re so different. We may superficially appear to exhibit certain things that are ours in different ways. But going deeper than that. …” Her voice trailed into an ellipsis.

Within that ellipsis, you have the essence of both Silverman’s play and the tantalizing pairing of its performers. A story of what happens when a meek Iowan homebody (Farrow) takes in a disruptive stranger from the Bronx (LuPone, natch) as a lodger, “The Roommate” ponders the Gordian knot of identity for two women at the crossroads of late middle age and the questions, as Silverman puts it, “of who gets seen and who doesn’t.”