Rosanna Arquette by Eric Charbonneau/ WireImage.com Rosanna Arquette by Eric Charbonneau/ WireImage.com

And Rosanna makes three as in, the third Arquette sibling to be involved in sister Patricia's soccer-mom-psychic thriller Medium. Rosanna will guest-star this spring as a "cougar" that prowls after younger men. She'll appear in Allison's dreams when her naughty activities turn deadly.

Patricia is thrilled that her sis is dropping by, this after brothers Richmond and David guested and directed, respectively. As she told the AP, "I'm really excited about this part they wrote for [Rosanna] because she is a very strong comedic and dramatic actress and this requires both elements." She also joked, "Of course, every time one of my siblings comes on set, the crew realizes that I have yet another [one] nicer than me." Rosanna's episode is scheduled to air April 7 on NBC. - Erin Fox

Do you love the Arquette family? If you could write a Medium role for Alexis, what would it be?

Related links:
" Watch episodes of Medium using our Online Video Guide.
" Read our in-depth recap of the latest Medium episode.