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Hilary Duff Reveals A Surprise Connection To Her Past In Her New Record

And it ain't about 'Lizzie.'

By Jessica Norton

Hilary Duff hit the studio with Ed Sheeran and Tove Lo to work on her sparkling, new comeback album Breathe In. Breathe Out. But another more low key collab she did may have you totally confused.

The last track on her album is a duet featuring Kendall Schmidt. You may remember him from the hit Nickelodeon television show and boy band Big Time Rush. Although it's a seemingly random pairing, the song has actually been a long time coming -- Let's go back, back to the beginning...

Last year Hilary recorded "Night Like This" and was in need of a dreamy counterpart to be the yin to her yang in the duet.

"It was actually one of the tougher songs to write on the album too, because I wanted it to be so conversational," she told MTV News of the song. "I knew I wanted it to be a duet, but it didn’t start out like, 'This is going to be for me and Kendall’ -- it was like, ‘Who’s going to do this? Ah, Kendall.’ He’s my good friend forever."

Kevin Schmidt, Kendall's brother, starred alongside Hilary in "Cheaper By The Dozen" back in 2003 -- and their families have been close friends ever since, so that's how they met in the first place.

After Big Time Rush, Kendall went on to pursue his indie pop side project Heffron Drive with his best friend Dustin Belt. So, it kind of just made sense for Kendall to slot into Hilary's track -- they're buds, and he's certainly got the chops.

"It was a real treat to be on it because I've known Hilary for like, I don't know, 15 years now so it's pretty cool," Kendall dished in a recent radio interview.

"I think it was based on a night that either Hilary had or wanted to have," he added. "[When] I was recording the song with her, she told me all about the feeling of it -- and there was even a time when I was singing a line and she was like, 'You know, imagine standing there with me, like you're saying this to me,' and I was like, 'OK, well I have to imagine how I would say that if I was on a date.'"

Kendall also gushed: "I'm so proud of it."