Little-known fact: A third Kerkovich sister has been floating around in the universe, and Happy Endings fans are about to lay eyes on her.

TVLine has learned exclusively that Law & Order: SVU‘s Stephanie March has been cast as Alex (Elisha Cuthbert) and Jane’s (Eliza Coupe) never-before-seen older sister, tentatively named Brooke.

RELATED | TVLine’s Renewal Scorecard: What’s Getting Axed? What’s Coming Back?

I’m told March’s arrival will shift the Kerkovich family dynamics in a major way, mostly because Brooke can out-Jane Jane.

The gig marks a rare small-screen comedy detour for March, who is mostly known for her dramatic roles. (As several TVLine readers pointed out below, she appeared in the first season of 30 Rock as a “love interest” for Liz.)

Happy Endings, which is currently on an unplanned hiatus, relocates to Fridays beginning March 29.

March’s episode will likely air in late April/early May.