Once Upon a Time fans have a little something extra to look forward to this November sweeps.

Series cocreator Adam Horowitz confirmed on Twitter this morning that Season 4’s eighth episode, titled “Smash the Mirror,” will run a full two hours, starting at 8/7c. (Felicity, cancel my church choir practice for that night!)

Horowitz stressed that this “bonus” hour is completely incremental to the season’s 22-episode run (which like Season 3 will air in two 11-episode batches).

UPDATE: ABC has since released a synopsis for the double-dip:

In Arendelle, when the Snow Queen tries to pit Elsa and Anna against each other and it proves more difficult than she anticipates, she takes drastic measures. Meanwhile, in Storybrooke Emma’s powers are out of control and her fear of hurting loved ones pushes her away from everyone she cares about. In her confusion, Emma turns to Gold for help getting her powers under control. Gold tells her about a way to get rid of her powers altogether and Hook tries to put a stop to it. Meanwhile, Regina struggles with her plan to find the author of the storybook until her quest takes an unexpected turn. Robin Hood recruits Will Scarlet to assist him on a mission and Mary Margaret and David search for Emma.

What do you suspect “Smash the Mirror” relates to? Is Sidney Glass’ world about to be shattered? Or could it be in reference to Maleficent, who in her day possessed a compact looking glass and is due to play a role in Season 4B?