Finian’s Rainbow, which opened Thursday, tells a charming, if implausibly benign, tale of greed, race relations, and the American Dream set in the segregated Deep South, in the fictitious town of Rainbow Valley. The show has garnered favorable reviews, mostly on the basis of the infectious music.

The Wizard of Oz-like backdrop doubled as the set for the commitment ceremony. White and Barnett processed from opposite stage wings to meet in the center, where they exchanged vows before the Reverend David Prince of Rutgers Presbyterian Church.

White serenaded Barnett with the classic “More Than You Know,” and the couple’s rings were delivered by 13-year-old cast member Christopher Borger.

Brett Berk, the gay son of Barnett, offered some words to the crowd.

“It appears as though my mother has officially out-gayed me,” said the VanityFair.com writer, before making more poignant observations.

“They’re each other’s perfect audience,” he said. “This is because they’re each other’s ideal stars.”

Afterward, misty eyes yielded to — what else? — necessity.

“I need a smoke!” exclaimed White as she exited the theater door and ran out to the street.