diff --git a/color/color-common.ts b/color/color-common.ts
index 837af9b46..fa7d56492 100644
--- a/color/color-common.ts
+++ b/color/color-common.ts
@@ -3,7 +3,7 @@ import types = require("utils/types");
 import knownColors = require("color/known-colors");
 
 var AMP = "#";
-var HEX_REGEX = /(^#[0-9A-F]{6}$)|(^#[0-9A-F]{3}$)/i;
+var HEX_REGEX = /(^#[0-9A-F]{6}$)|(^#[0-9A-F]{3}$|(^#[0-9A-F]{8}$)/i;
 
 export class Color implements definition.Color {
     private _a: number;
@@ -108,7 +108,11 @@ export class Color implements definition.Color {
         return value1.equals(value2);
     }
 
-    public static isValid(value: string): boolean {
+    public static isValid(value: any): boolean {
+        if (types.isNullOrUndefined(value) || value instanceof Color) {
+            return true;
+        }
+
         if (!types.isString(value)) {
             return false;
         }
diff --git a/color/color.d.ts b/color/color.d.ts
index f97088317..5b97b5bfc 100644
--- a/color/color.d.ts
+++ b/color/color.d.ts
@@ -70,9 +70,9 @@ declare module "color" {
         public static equals(value1: Color, value2: Color): boolean;
 
         /**
-         * Validates if a string value can be converted to color.
+         * Validates if a value can be converted to color.
          * @param value Input string.
          */
-        public static isValid(value: string): boolean;
+        public static isValid(value: any): boolean;
     }
 }
\ No newline at end of file