Tonight's episode of hit ABC medical drama "Grey's Anatomy" promises to be an exciting one, but also a difficult one for Alex and Joe. For spoilers from Justin Chambers, who plays Alex on the show, and Camilla Luddington, who plays Jo on the show, read on.

Luddington and Chambers recently sat down with TV Guide for an interview where they revealed some spoilers about tonight's episode. It seems new rules at the hospital will prevent the two from being allowed to date. Luddington explained how Jo will react.

"Jo assumes by process of elimination that it's Stephanie because of everything that happened with April and Jackson [Jesse Williams]. She feels betrayed a little bit by her friend. Jo feels like there haven't been many good relationships in her life, so Alex is someone who is beyond special to her. It's not just a boyfriend that she's in love with. For someone to potentially threaten that in a way that she feels is selfish, ridiculous and over the top, she feels betrayed. She's really upset. She's a little vicious about it," the actress said.

Chambers discussed how Alex will deal with the hardship.

"Commitment phobias are still [there]. I think they make a great couple and complement each other," the actor said. But will they be able to stay together? 

Tune in tonight at 9/8c on ABC to catch the all new episode of "Grey's Anatomy."