Kiernan Shipka is summoned to Riverdale by Cheryl Blossom

It's almost time! Have a peek at the first look of Kiernan Shipka's guest appearance in the long-awaited special crossover episode between the iconic Robert Aguirre-Sacasa projects, Riverdale and Chilling Adventures of Sabrina.

On Dec. 7, the highly anticipated Riverdale (or Rivervale as it's currently known) Chilling Adventures of Sabrina will finally air!  The fourth episode of Season 6, titled "The Witching Hour(s), is part of the CW drama's special five-episode event.

The penultimate episode will explore the supernatural genre as Greendale's witch Sabrina (Kiernan Shipka) and Cheryl Blossom (Madelaine Petsch) team up on a dangerous spell.

"As Bailey's Comet passes over Rivervale, Cheryl and Nana Rose (Barbara Wallace) revisit the tragic stories of the Blossom women through the years. Meanwhile, the once-in-a-lifetime celestial event prompts Cheryl to summon a familiar face to Rivervale – Sabrina Spellman," the episode's description reads.

News of the crossover, directed by James DeWille and written by Arabella Anderson, was first shared in October by executive producer and creator Roberto Aguirre-Sacasa.

Watch the preview below!