They've been friends for 10 years, they're on tour together [1], and now Demi Lovato [2] and Nick Jonas [3] can check an appearance on James Corden's Carpool Karaoke [4] off their list.

Naturally, they sang (read: slayed) some of their hits, including "Stone Cold" and "Close," but the true highlight was Demi's hilarious decision to tease Nick about his teenage dating life, which, if you remember, was a purity-ring-filled Disney love triangle, starring Selena Gomez [5] and Miley Cyrus [6]. Here's how it went down:

James: "Nick, you're dating seemingly everyone. And then who else?"

Demi: "Miley. And then back with Selena."

Nick: "Thank you, Demi."

Demi: "And then back with Miley."

Confused, James asks Demi to walk him through it. "It was Cyrus, Gomez, Cyrus, Gomez, and then I don't know what else happened," she quips. What would a long-term friendship be without a little teasing, right? Press play above to watch the full thing unfold, and then relive their entire friendship [7].