Beyoncé dropped a big surprise on Saturday when she announced the debut of some sort of project titled Lemonade on HBO. The “world premiere event” is set to air April 23 at 9 p.m. ET.

While fans need to wait five days until its debut and with speculation running high as to the content of Lemonade, EW has learned a few details about the project.

A source tells EW, “Beyoncé’s super top secret Lemonade is actually a lengthy concept video.”

On Sunday, Beyoncé, who most recently released the epic video for her new single “Formation” in February, dropped an an extended trailer of Lemonade. The one-minute long clip shows footage of Beyoncé, decked out in fur, whispering, “The past and the present merge to meet us here. What are you hiding?” The trailer is inter-spliced with ominous footage of a thunderstorm and Beyoncé wielding a bat as explosions go off in the street.

The pop star’s HBO event comes just days before the launch of her world tour, which kicks off April 27 in Miami.