Aly & AJ finally revealed which song was inspired by AJ’s mid-2000s breakup with Joe Jonas.

Tthe sister pop duo made the revelation when they responded to popular YouTuber Elle Mills’ tweet concerning their cult pop hit “Potential Breakup Song.”

"Okay, so you’re telling me that I went 13 years not knowing that one of the greatest songs ever written was about Joe Jonas this entire time?” Mills tweeted on April 2.

On April 9, one of the sisters replied to Mills, sharing that “Potential Breakup Song” was not written about the middle Jonas brother, but rather that their song “Flattery” was.

The 2007 album track off Insomniatic asks a former flame to stop flattering himself and just admit that he's not okay after a breakup: "I can forgive it, I can't forget it / You left me here with all these scars / And you can't deny the hardest part: I'm not in your arms," the sisters sing on the track.

Listen, below:

The Michalka sisters met the Jonas Brothers after they both were signed by Disney's Hollywood Records. They toured together for the first time in December 2005 on the Cheetah-licious Christmas Tour. AJ and Joe began dating shortly after meeting, before ending things around November 2006.

AJ even previously admitted that he was her first kiss.

Although the song portrayed a bad breakup, the sisters and brothers are now on great terms, even attending each others' shows.