Patti LaBelle and Mariah Carey set social media on fire after an impromptu duet on Instagram. LaBelle appeared backstage while supporting Carey, whom she often refers to as her goddaughter, after the singer's Caution World Tour stop in Philadelphia last week.

Both divas sipped wine as they began singing the lyrics to Carey's 2018 single "With You." "Shots of Remy, playing 'Confessions' and our bodies blendin," they sang.

Carey left her godmother stunned as she continued, "Ooh, I'm in love, it's true. Yeah, damn, I f**ks with you." LaBelle immediate gasped and asked Carey, "Oh, you say F with you?" Once Carey confirmed the explicit word's presence in the song, she joked, "See, she didn't know I said that! Cut it out!"

Despite the dropping the "F" bomb, the duo kept singing, "And we all make mistakes sometimes, but we muddle through. I don't know what I'm supposed to do, oh baby, I'm in love, it's true."

This isn't the first time fans have gotten a glimpse into how close the relationship between the two auoerstars are. In January, LaBelle opened up about mentoring her goddaughter during the E! News' series Busy Tonight.

"Mariah is my goddaughter. I had to slap her every now and then," LaBelle revealed. "She's so phenomenal and so good, she doesn't need to be slapped anymore. That's my baby."