Kelli O’Hara made the most of her Monday night off from “South Pacific.” It started at the Metropolitan Museum of Art’s Costume Institute Gala, where she became part of the “superhero” fashion brigade in a red Michael Kors gown. But there was no after-party with George Clooney on her agenda. At a quarter to midnight, she hit the stage of Joe’s Pub, having changed into jeans and a blue silk halter top, to celebrate her new CD, “Wonder in the World,” which went on sale yesterday.

“The title, I’m not referring to myself there,” she said onstage at the sold-out show, although the transformation she’d just accomplished seemed Wonder Woman-ish. “It’s the title of a song on the album, written by Harry Connick Jr.,” Ms. O’Hara continued. There are probably plenty of people who’d feel comfortable calling Ms. O’Hara a wonder, but she is not one of them.

The remark was typical of her down-to-earth, funny banter and antics throughout the show: She munched on Cool Ranch Doritos, donned a cowboy hat, and even pretended to go into labor, singing what she described as an eclectic mix of songs chosen because “they’re from the heart.” The album includes “Fable” by Adam Guettel, from “Light in the Piazza,” as well as “And So It Goes” by Billy Joel.

She was tender when she introduced a song she wrote, “Here Now,” which she said is in honor of her grandfather, who used to say “here now” a lot. He left school in the eighth grade to work on the family farm, and later watched from the fields as his high school class graduated. “I think he made that sacrifice so I could be here now,” she said.

Ms. O’Hara threw in a wonderful Broadway story, too, about the time she visited the Broadway lyricist Betty Comden, shortly before she passed away. Ms. O’Hara, who at the time was in “Light in the Piazza,” which featured Comden’s work, had come to her home to sing the music from the show, because Comden was not well enough to attend a performance. “I sat on her chaise lounge and I sang this, and she smiled,” Ms. O’Hara said. “Now that’s what music is all about,” she added, before launching into “Make Someone Happy.”

And there was a song with the man who inspired her to record an album: her husband, singer-songwriter Greg Naughton.

“I am madly in love with him,” she said before he came out onstage to join her for a song he wrote, “The Sun Went Out.” The two looked at each other, and all of the sudden it was as if the audience had disappeared.