Tim Miller will not be returning to direct “Deadpool 2,” dropping out of the sequel due to a series of creative differences with star Ryan Reynolds, a source confirmed Saturday morning.

While Miller had not formally signed on the helm the sequel, he was in the process of developing the script and was widely expected to return. The source said the split with the project was amicable.

After “Deadpool’s” massive box office success, a sequel was nearly inevitable, and was announced at CinemaCon back in April. There, Fox co-chairman Stacy Snider confirmed that Reynolds would be back, as well as Miller.

Miller gave Fox its biggest hit of the year with “Deadpool,” which grossed a whopping $786 million worldwide after opening on Valentine’s Day earlier this year. It’s the seventh-highest-grossing movie of 2016, and the highest-grossing R-rated film ever on worldwide basis.

Most of the creative team was set to return for “Deadpool 2,...