Looks like blood isn’t the only thing that Meredith and Maggie share. During the Season 12 finale of ABC’s “Grey’s Anatomy” it was revealed that both sisters caught feelings for the same guy: Dr. Nathan Riggs.

Maggie (Kelly McCreary) shared her feelings for the New Zealand doctor with Meredith (Ellen Pompeo) during Owelia’s wedding. However, the newly single surgeon decided to keep her fling with Riggs (Martin Henderson) under wraps, not wanting to upset her hopeless romantic sister. But when news of Meriggs’ romance finally does comes to light in Season 13 — and it will during episode 2 of the medical series — McCreary revealed that Maggie won’t be too pleased that her sister kept her in the dark.

“One of the things that we know about Maggie is that she is really a stickler for honesty and the truth,” the actress told TV Guide. “In her first season, she really holds it against Richard (James Pickens Jr.) that he didn’t tell her [he was her father] right away, that he withheld the truth for any length of time. To me, that’s an indication of how we can expect Maggie to feel about any lack of honesty, any lack of full transparency and disclosure in a relationship — especially with somebody that she trusts and, more than trusts, really relies upon as much as Meredith.”

But it looks like Maggie won’t be the only one crushed by Meredith and Riggs’ romance. In July, Kevin McKidd, who portrays Owen, dished that he won’t be fond of his sister-in-law dating his arch nemesis. “I don’t think Owen is going to be happy about that,” he told Entertainment Weekly. “He’s almost becoming an unofficial brother to Meredith. Derek (Patrick Dempsey) was his friend. He’ll be a bit territorial, to be honest.”

Another reason Owen will find it hard to accept their relationship is because the last person Riggs dated was Owen’s sister Megan — and she died. “He might be a little irrational when he finds out [about Meredith and Riggs],” he added.

“Grey’s Anatomy” will return to ABC with its Season 13 premiere on Thursday, Sept. 22, at 8 p.m. EDT.