Watch "Disenchanted" Stars James Marsden and Idina Menzel Spontaneously Sing an "Aladdin" Duet

Idina Menzel and James Marsden just thrilled musical-theater-lovers' hearts everywhere with an impromptu duet of "A Whole New World" from "Aladdin" on "The Late Late Show With James Corden." In a Nov. 17 appearance, the two "Disenchanted" stars discussed their love of all things theatrical, and near the end of the segment, Marsden persuaded Menzel to join him in a sing-along of the "Aladdin" classic.

"He's just a real pain," Menzel said of Marsden, "and Amy Adams, too. They were both singing and dancing, even when they said cut."

"Amy and I were such super fans of Idina that when they would yell cut . . . or in the makeup trailer or whatever, we'd go to Idina and say, 'Hey, will you sing a song with me?'" Marsden said, going on to break out into the beginning of "A Whole New World." Menzel quickly joined him, even breaking into harmony during the chorus.

Prior to their duet, the pair discussed their various insecurities when it comes to musical theater, with Menzel saying she actually isn't a great dancer. "I have to be tutored," she laughed. Marsden, for his part, shrugged off Menzel's compliments on his voice and confessed that he hadn't thought of himself as singer as a child, though he often tried to channel various musicians like Frank Sinatra. He then went on to do an impression of John Legend's "All of Me," thoroughly impressing Corden.

Menzel and Marsden were promoting their upcoming movie "Disenchanted," which has plenty of musical numbers of its own. "It's 15 years later," Marsden said of the "Enchanted" sequel, "and it's sort of a story of what happens after happily ever after. Maybe the blush has fallen off the rose a bit in our relationships."

"But not ours," Menzel said quickly. Menzel and Marsden's characters, Nancy Tremaine and Prince Edward, made an unlikely couple in 2007's "Enchanted."

Previously, Marsden told POPSUGAR that Menzel will finally get her own song in "Disenchanted." "The elephant in the room is Idina is in the first movie and doesn't sing a note," he said.

"I was happy to just be hired as an actor [in 'Enchanted'], not for singing," Menzel told us then. "But I'm happy I have a song now." Marsden replied, "I think everyone will be very, very happy about that."

"Disenchanted" is now streaming on Disney+.