diff --git a/src/libImaging/Unpack.c b/src/libImaging/Unpack.c
index c23d5d889f6..e9203fe4d74 100644
--- a/src/libImaging/Unpack.c
+++ b/src/libImaging/Unpack.c
@@ -1695,6 +1695,7 @@ static struct {
 
 #ifdef WORDS_BIGENDIAN
     {"RGB", "RGB;16N", 48, unpackRGB16B},
+    {"RGB", "RGBX;16N", 64, unpackRGBA16B},
     {"RGBA", "RGBa;16N", 64, unpackRGBa16B},
     {"RGBA", "RGBA;16N", 64, unpackRGBA16B},
     {"RGBX", "RGBX;16N", 64, unpackRGBA16B},
@@ -1708,6 +1709,7 @@ static struct {
     {"RGBA", "A;16N", 16, band316B},
 #else
     {"RGB", "RGB;16N", 48, unpackRGB16L},
+    {"RGB", "RGBX;16N", 64, unpackRGBA16L},
     {"RGBA", "RGBa;16N", 64, unpackRGBa16L},
     {"RGBA", "RGBA;16N", 64, unpackRGBA16L},
     {"RGBX", "RGBX;16N", 64, unpackRGBA16L},