"Grey's Anatomy" lovebirds Alex and Jo have been having a smooth ride for the past couple of seasons, and therefore season 12 might be the apt time to start worrying about their future, believes actress Camilla Luddington.

Because no "Grey's Anatomy" couple has had a smooth ride so far, Luddington feels that season 12 could probably see Alex and Jo's relationship coming under strain.

"I'm nervous because Jo and Alex have had three seasons of being pretty good like, which is really unusual on Grey's. They've had issues, but they've gotten over them. So, that makes me think that they moved in together I just don't trust that things are going to continue to go well," she told TV Line.

Jo wants to stay in Seattle and put down roots, and she bought the house in the previous season to see if Alex would want to take the next step in their relationship.

In a recent interview, The Hollywood Reporter asked Luddington whether or not Jo's house purchase was to see if Alex would settle down with her.

"She's definitely saying that now she wants to put down roots; she's very serious about that. She's crazy about Alex and you hear her say she loves Alex. I don't think she's leaving," the actress told The Hollywood Reporter in an earlier interview.

Speculations are rife that the two will face a lot of problems in the upcoming season, but chances are also high that Jo and Alex would walk down the aisle at the end of the season.

As for what's in store for other characters, chances are Meredith's Alzheimer's storyline will progress in season 12. A few seasons back ,Meredith got tested for the Alzheimer's gene, and not surprisingly, she tested positive for multiple genetic markers of the disease. Since then she has made multiple references to the possibility of her dying similar to how her mother passed away.

However, before Meredith succumbs to Alzheimer's, chances are that she would once again find love, possibly with Martin Henderson's character.

"Grey's Anatomy" will return to ABC on 24 September.