Guess who's coming to Seattle Grace Hospital?

Grey's Anatomy Dr. Sheperd will be reunited with Private Practice's Dr. Shepherd. It's brother-sister reunion happening at this season's cross-over. Caterina Scorsone, who plays Amelia Shepherd, revealed that the estranged siblings will indeed reunite, thanks largely to the prodding of Derek's ex-wife Addison!

"Basically, Addison kicks her in the keester," Scorsone told E! Online in an exclusive interview.

"Amelia is kicking and screaming and doing everything she can do to avoid the inevitable, but Addison somehow convinces her that she's gotta go to Seattle." So...blame Addison. Or rather, thank her."

According to Scorsone, the two neurosurgeons had a falling out after the death of their father, who was previously revealed to had been killed in a robbery. The cross-over episode promises to reveal more insights on Dr. Derek Sheperd, played by Patrick Dempsey, and fans might now know why Dr. McDreamy's eyes are at times, so sad.

However, followers of Grey's Anatomy and Private Practice will have to wait for a few more months for the cross-over episode. Private Practice premier its new season on Thursday (September 22) on ABC right after a new Grey's Anatomy episode at 9 p.m.