diff --git a/Tests/test_imagepalette.py b/Tests/test_imagepalette.py
index d4d6922c8..5152abf56 100644
--- a/Tests/test_imagepalette.py
+++ b/Tests/test_imagepalette.py
@@ -29,6 +29,8 @@ def test_getcolor():
     rgba_palette = ImagePalette.ImagePalette("RGBA")
     assert rgba_palette.getcolor((0, 0, 0)) == rgba_palette.getcolor((0, 0, 0, 255))
 
+    assert palette.getcolor((0, 0, 0)) == palette.getcolor((0, 0, 0, 255))
+
     with pytest.raises(ValueError):
         palette.getcolor((1, 2, 3))
 
diff --git a/src/PIL/ImagePalette.py b/src/PIL/ImagePalette.py
index 03ffef099..36b536fb6 100644
--- a/src/PIL/ImagePalette.py
+++ b/src/PIL/ImagePalette.py
@@ -105,8 +105,12 @@ class ImagePalette:
         if self.rawmode:
             raise ValueError("palette contains raw palette data")
         if isinstance(color, tuple):
-            if self.mode == "RGBA" and len(color) == 3:
-                color += (255,)
+            if self.mode == "RGB":
+                if len(color) == 4 and color[3] == 255:
+                    color = color[:3]
+            elif self.mode == "RGBA":
+                if len(color) == 3:
+                    color += (255,)
             try:
                 return self.colors[color]
             except KeyError as e: