NEW YORK (Reuters) - By merely striding onto a stage, Liza Minnelli transformed a Manhattan concert hall into a cabaret on Wednesday, as the legendary entertainer teamed up with Broadway veteran Alan Cumming for the first night of a two-night gig reprising a show the pair put on last summer at a Fire Island nightclub.

"Liza coming to Fire Island - can you imagine? It was like a papal visit," Cumming said, recalling the friends' two shows that spawned the sold out shows at Town Hall on Wednesday and Thursday.

"I think this is probably the first time that a show has transferred from Cherry Grove, Fire Island to Broadway," Cumming said, referring to the almost exclusively gay beach town where the friends appeared during a July heat wave, cooling down between sets in a walk-in refrigerator.

The concert served as a "Cabaret" reunion of sorts, as Minnelli, still closely associated with her Oscar-winning performance as Sally Bowles in the 1972 film of the iconic musical, and Cumming, who won a Tony award as the emcee in the acclaimed Broadway revival more than two decades later, sang duets including the title song, "Cabaret."

But the pair toyed with sexual identity, as Minnelli, who has a huge gay following, and Cumming, who is married to his male partner, switched their "Cabaret" roles - she sang "Willkommen," usually sung by the emcee, while he sang "Mein Herr," one of Sally's big numbers.

Minnelli's husky intonations contrasted dramatically with Cumming's reedy tenor for their duets, which were augmented by little waltzes and plenty of banter and embracing.

"We're just crazy about each other," Minnelli told Reuters after the show. "It felt very intimate, like being with a bunch of friends."

Before the show, producer Daniel Nardicio said "It had always surprised me that no producer had thought to put these two long-time friends on stage together ... That's what people saw on the stage on Fire Island - two good friends having fun. I dare say that this show is a celebration of friendship."

"I never know what he's going to do. And he never knows what I'm going to do," Minnelli reflected about the concert's free-wheeling vibe.

Still, she noted, "It's a very well-paced show," adding, "Was it OK?", mirroring her on-stage apparent insecurity as she asked an audience of adoring fans: "I hope I'm doing OK for you?"

By all accounts it was more than OK, as the crowd leapt to its feet en masse to give Minnelli a standing ovation after nearly each one of her songs, which included "But The World Goes Round" and one of her signature songs, "New York, New York," as well as "Teach Me Tonight," "Liza with a Z" from the television special of the same name, and the novelty tune, "Ring Them Bells" from the same program, which won her an Emmy.

Minnelli, who has triumphed as a singer, actress and dancer on both stage and film, much like her legendary mother Judy Garland, said she doesn't hew to one particular form.

"It's all one thing - when I'm singing I'm acting, and when I'm dancing I'm acting," she said.

Before her set, Cumming, who first met Minnelli when she saw him in the "Cabaret" revival, sang an impassioned version of "Losing My Mind" from "Follies" as well as what he called a mashup of Lady Gaga's "The Edge of Glory" and Adele's "Someone Like You," among other songs.

The night ended with Cumming leading the sold out crowd in serenading Minnelli with "Happy Birthday," in honor of her 67th birthday on Tuesday.

Minnelli said she didn't know about taking their show further. "We really haven't even thought about it. I guess it would depend on scheduling," she said, before saying again how terrifically close the two stars are.