Worrying news about the Deadpool sequel: Director Tim Miller has stepped off the project.

According to The Hollywood Reporter, Miller has left Deadpool 2 due to “creative differences with Ryan Reynolds,” the actor who plays the merc with the mouth. THR’s sources say Miller and Reynolds have “increasingly butted heads over certain creative issues” as pre-production moves forward.

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Though Reynolds is credited with the film’s success thanks to the unique Deadpool personality he brought to the screen, there’s no doubt that losing an important collaborator is a bit worrying.

Deadpool is slated to begin filming in early 2017. Fox hasn’t set a release date for the film yet.

Deadpool 2 will be a major film for Fox after the original was a box office smash — it made $782 million worldwide on a $58 million budget.

We’ll let you know once a new director is hired.