By Nolan Feeney
March 16, 2017 at 05:45 PM EDT
Credit: Jacopo Raule/Getty Images

Chloe x Halle are taking a play from the book of Beyoncé.

The sister duo surprise-released a new mixtape, titled The Two of Us, Thursday afternoon — or, at least, they’re calling it a mixtape in a video description on YouTube, where they’ve uploaded 25 minutes of new music. On their website, Chloe x Halle are more ambiguous about how to classify the body of work: “This is not an album…. not really a mixtape either.” Currently, The Two of Us is only available on YouTube, not on iTunes or streaming services.

Chloe, 18, and Halle Bailey, 16, first attracted Beyoncé’s attention by covering her on YouTube before later signing with the superstar’s Parkwood Entertainment label. (Other signees include rapper Ingrid and singer-songwriter Sophie Beem.) Beyoncé wasn’t their only co-sign, either: The singers appeared on “This Is For My Girls,” the Diane Warren-penned song former FLOTUS Michelle Obama had commissioned in support of her #62MillionGirls campaign last year.

The group’s Sugar Symphony EP, which featured their breakout single “Drop,” arrived last April. Hear The Two of Us above.