"Once Upon a Time" alum Jennifer Morrison is joining the cast of NBC's "This Is Us" in Season 4.

The actress, whose credits also include "House" and "How I Met Your Mother," will have a recurring role in multiple episodes. Details about her character have not yet been revealed.

Last month, NBC gave "This Is Us" an unprecedented three-season renewal. The hit family drama's Season 4 premiere, which was announced last week, is September 24.

As for the character Morrison might be playing, fans are already speculating that it could be Kevin's baby mama (the Season 3 finale flashforward revealed he has a teen son) or Rebecca's sister.

Morrison next appears in "The Report" opposite Adam Driver and Annette Bening and directs and upcoming episode of HBO's "Euphoria."