Credit: David Livingston/Getty Images Photo: Caterina Scorsone at the Disney ABC Television Group's Summer TCA Party on August 1, 2010

Little Shepherd is here to stay! TV Guide reports that when ABC's Private Practice returns for Season 4, Caterina Scorsone, who plays Derek Shepherd's younger sister Amelia, will be a series regular. A neurosurgeon who favors risky procedures, Amelia has a past even darker than Derek’s.

Caterina Scorsone has been acting since the age of 8, and before landing the role of Ameila, she starred in SyFy's Alice. If Private Practice's medical jargon seems to roll off her tongue, it might have something to do with the fact that Caterina attended medical school IRL. Impressive!

Amelia is close with her former sister-in-law, Addison Montgomery (Kate Walsh), but we'd love to see her interact with Meredith. Indeed, Shona Rhimes says a Grey's Anatomy-Private Practice crossover event reuniting the estranged siblings might be in the works. "I would love to see what happens when Derek, his sister, and their mom — because I love Tyne Daly — get together," Rhimes divulged. "I think that would be very interesting to see. We're talking about possibly thinking about that for next season." Maybe Derek can return this black sheep to the Shepherd fold!

Source: TV Guide