As Meredith Grey (Ellen Pompeo) and Nathan Riggs (Martin Henderson) get closer, the drama surrounding them intensifies. Actor Kevin McKidd shared his thoughts about how his character Owen Hunt would feel about the couple in the upcoming season 13 of "Grey's Anatomy."

Owen and Nathan were friends in the past, but something happened that broke their brotherly relationship. As they try to mend some wounds, another one will seem to open with Meredith and Nathan getting closer to each other. While no one knows yet about Meredith and Nathan's growing affection, McKidd said "That's going to come out, I'm sure, next season."

"I don't think Owen is going to be happy about that. He's almost becoming an unofficial brother to Meredith. Derek was his friend," McKidd said as reported by Entertainment Weekly. Derek Shepherd was Meredith's deceased husband who was portrayed by actor Patrick Dempsey.

McKidd continued "He'll be a bit territorial, to be honest. Also, the last time Riggs got close to somebody Owen cares about, she died. He might be being a little irrational when he finds out."

Nathan was the boyfriend of Owen's sister Megan, who rode on a helicopter and was never found. Megan caught Nathan cheating and rode on the helicopter carrying a passenger despite the bad weather to get away from him. Although Nathan's participation in Megan's demise was circumstantial, Owen never stopped blaming him for it.

Aside from Owen, Meredith's sister, Margaret Pierce (Kelly McCreary) will also come in the way of the two. Margaret also likes Nathan a lot and she has confided in Meredith about what she feels. Added to that, she thinks Nathan likes her back.

"Grey's Anatomy" season 13 is scheduled to premiere on Sept. 22 at 8 p.m. on ABC.