diff --git a/lib/extract/extractColor.js b/lib/extract/extractColor.js
index 7ba37bac..589cfb91 100644
--- a/lib/extract/extractColor.js
+++ b/lib/extract/extractColor.js
@@ -387,7 +387,7 @@ function rgbFromHwbString(string) {
   const w = clamp(parseFloat(match[2]), 0, 100);
   const b = clamp(parseFloat(match[3]), 0, 100);
   const a = clamp(isNaN(alpha) ? 1 : alpha, 0, 1);
-  return hwbToRgb([h, w, b, a]);
+  return [...hwbToRgb([h, w, b, a]), a];
 }
 
 function colorFromString(string) {