diff --git a/PIL/_imaging.pyi b/PIL/_imaging.pyi
index 9e95bdba0..2b2eb8baf 100644
--- a/PIL/_imaging.pyi
+++ b/PIL/_imaging.pyi
@@ -14,6 +14,9 @@ def alpha_composite(core1: ImagingCore, core2: ImagingCore) -> ImagingCore: ...
 def blend(core1: ImagingCore, core2: ImagingCore, alpha: float) -> ImagingCore: ...
 def fill(mode: Mode, size: Size, color: Any) -> Any: ...
 def new(mode: Mode, size: Size) -> ImagingCore: ...
+def merge(mode: Mode, im1: ImagingCore, im2: ImagingCore=...,
+          im3: ImagingCore=..., im4: ImagingCore=...) -> ImagingCore: ...
+### FIXME: Are these merge values defaults or Optional?
 
 def map_buffer(target_data: Any, size: Size, decoder_name: Text,
                bbox: Optional[Any], offset: int, args: Tuple[Mode, int, int]