Clarkson told the crowd that, as part of her tour, she takes requests from fans in each city. Since she was in New York, one fan suggested she sing a Broadway song, but they didn't name which song. Clarkson seemed delighted to have the chance to pick her own song.

The pop singer confessed she grew up performing in musicals, adding that she would love to do Broadway in the future. "I love Broadway musicals. I can't wait to be in a musical, I really want to be in one," she said.

"This might not be a very well-known [song], but if you're a Broadway nerd like me, then it will be," Clarkson said, before asking, "Does anyone like Funny Girl?" The audience erupted in cheers. She told the audience that Funny Girl was one of her favorite shows and that she was a huge Barbra Streisand fan; Clarkson noted that the two also share a birthday.

Clarkson then performed "My Man," the signature Fanny Brice song that was not featured in the Broadway score of Funny Girl, but was included in the film.

Here's a look at Clarkson's Radio City moment: