Owen (Kevin McKidd) must be floating on cloud nine after getting to lock lips with Amelia (Caterina Scorsone) in the Season 12 premiere of “Grey’s Anatomy.” But according to reports, the Head of Trauma will soon find himself drifting from a dream-like state into a nightmare when the doctor’s past starts to haunt him in an upcoming episode of the hit ABC series.

The actor revealed to TVLine on Saturday that “somebody comes along during the season from Owen’s past” who will shake things up for the red headed doc – and not in a good way. McKidd elaborated, explaining that the newcomer “ignites a lot of things in Owen and causes real problems from him.”

But who exactly is this troublesome person? And what period of Owen’s life are they from? Perhaps the upcoming character used to work alongside Owen in the army and will trigger the doctor’s PTSD when they show their face in the halls of Grey Sloan Memorial Hospital.

“I don’t quite know,” McKidd revealed, adding that he too was in the dark regarding the upcoming drama. “But Owen doesn’t react particularly well.”

Maybe the person set to cause problems for Owen will be none other than Martin Henderson’s character, who will be joining the other scrub-sporting docs midseason. In June, TV Guide confirmed that the New Zealand-native was cast in Season 12 of “Grey’s Anatomy” as the hospital’s newest surgeon.

Initially fans thought Henderson was cast as Meredith’s (Ellen Pompeo) new love interest following the death of Derek (Patrick Dempsey). However, Shonda Rhimes, mastermind behind the medical series, shut down those rumors, insisting that she wasn’t planning on introducing a new romantic interest for Meredith anytime soon.

“That’s not really the focus of what we're doing with her right now,” she told E! News.

So, if Henderson isn’t Mer’s new beau, is it possible he could be a blast from Owen’s past?

“Grey’s Anatomy” airs Thursday nights at 8 p.m. EDT on ABC.