Agatha All Along features Kathryn Hahn as Agatha Harkness to introduce additional facts regarding Agatha's development within WandaVision.

So Agatha Harkness is dead, but her spirit continues ... and Sharon on a stone pentagram in Agatha’s basement. Together, they ...

Hahn first debuted as Agatha Harkness in the aforementioned Elizabeth Olsen and Paul Bettany-led Disney+ series, and her character was such a hit that it led to a spin-off of her own, Agatha All ...