During a interview with Comic Book Resources Zimmer confirmed he will in fact being scoring Batman v Superman: Dawn of Justice, but he won’t be scoring all of it. In the interview Zimmer stated he didn’t want to betray his worked with Christopher Nolan on The Dark Knight series so in hand he won’t be scoring for Batman in the film, he’s given the task fully to Junkie XL.
You know something? I have agonized over it. I agonized over it, so much so that finally, I went, I don’t want to betray what Chris, James Newton Howard and I did. And so I asked Zack [Snyder] if it would be OK if I called a friend in. And I’m going to be working with Junkie XL, who really is a great friend. He just finished the Mad Max score. I said to him, “You take care of Batman. I’ll do the other guy.” And Zack loved that idea. It’s a way out.