The ABC drama will now reveal who killed Daniel Grayson (Joshua Bowman) in the 15th episode, according to Entertainment Weekly.
"Initially, before we got our full-season pickup, I wanted [the mystery reveal] to be episode 13," Kelley explained. "In case the show was only hitting for a smaller number of fans, I wanted to be able to satisfy the people who had tuned in and make sure it had bookends. But we're finding we have so much story to tell."
He added that the show will now take the opportunity to focus more on Tyler (Ashton Holmes).
"[His arc] becomes bigger and bigger," Kelley revealed. "In order to service that, we needed to push the engagement party on the beach just a couple of episodes. It hasn't changed the story we want to tell. It's just that we found we had more story to tell."
Rescue Me actor James McCaffrey recently signed up to play the recurring role of scheming attorney Ryan Huntley on Revenge.
The series continues on Wednesdays at 10/9c on ABC.
> Emily VanCamp teases Revenge love triangle
Watch a clip from Revenge below: