Time to stock up on wine and popcorn! In just a few days “Grey’s Anatomy” will return to the small screen to stir up more drama with its Season 12 winter premiere. And while we’re anxious to learn Meredith’s (Ellen Pompeo) fate (a midseason trailer showed the surgeon getting brutally attacked by an unruly patient) we’re also looking forward to the ABC drama tying up the loose ends from its cliffhanger-riddled winter finale.

In episode 8, a branch from Owen’s (Kevin McKidd) mysterious family tree was unveiled. Apparently the redheaded doctor has a sister — one he’s been keeping a secret for seven seasons! But why has Owen stayed tightlipped about the existence of his sibling all these years (that is, if she’s even alive …)? Fans will find out when “Grey’s Anatomy” returns Thursday, Feb. 11.

But before the Shonda Rhimes medical drama airs its midseason premiere, here’s everything you should know about Owen’s sister:

Riggs (Martin Henderson) Is Not Owen’s Sister!

There’s no transgender twist in this storyline. At the Television Critics Association winter press tour, Henderson, who plays the Grey Sloan newcomer, revealed to TVLine that he’s not Owen’s sister.

“While it would be nice to have the opportunity to play such complexity on network TV, I sadly doubt it will be as controversial or topical as that,” Henderson explained while McKidd confirmed that specific subplot was “off the table for sure.”

Riggs Did Have A Relationship With Owen’s Sister

If you thought there was something off about Riggs calling Owen’s mother (Debra Mooney) “ma” then you were right. McKidd told the Hollywood Reporter that Riggs was “romantically involved” with his character’s sister … until “something happened — something Owen can’t forgive or reconcile in himself, and that’s what’s exciting to find out.”

Is Owen’s Sister Alive?

Although McKidd teased there’s “nothing definite about the fate” of Owen’s sister, Henderson did reveal to Entertainment Weekly that something disastrous happened involving Owen’s sibling.

“All we know is there was something in our past — some collective shared event — involving Owen’s sister that was tragic for the both of them,” he began. “They both have very different perspectives of what the actual circumstances were.”

What Was Owen’s Relationship With His Sister Like?

Owen may have never spoken about his sister but that doesn’t mean he didn’t love her. According to the actor, Owen and his sister were close. “That’s why Owen is in such a state over this,” he told the Hollywood Reporter. “They were very tight.”

Fans will learn more about Owen's sister when “Grey’s Anatomy” airs its Season 12 winter premiere on Thursday, Feb. 11, at 8 p.m. EST on ABC.

RELATED STORIES