diff --git a/lodash/lodash-tests.ts b/lodash/lodash-tests.ts
index f94a7596d..edef9c3c6 100644
--- a/lodash/lodash-tests.ts
+++ b/lodash/lodash-tests.ts
@@ -1196,6 +1196,12 @@ result = <boolean>_({}).isRegExp();
 result = <boolean>_.isTypedArray([]);
 result = <boolean>_([]).isTypedArray();
 
+// _.isUndefined
+result = <boolean>_.isUndefined(any);
+result = <boolean>_(1).isUndefined();
+result = <boolean>_<any>([]).isUndefined();
+result = <boolean>_({}).isUndefined();
+
 // _.lt
 result = <boolean>_.lt(1, 2);
 result = <boolean>_(1).lt(2);
@@ -1444,8 +1450,6 @@ result = <boolean>_.isPlainObject({ 'name': 'moe', 'age': 40 });
 
 result = <boolean>_.isString('moe');
 
-result = <boolean>_.isUndefined(void 0);
-
 result = <string[]>_.keys({ 'one': 1, 'two': 2, 'three': 3 });
 result = <string[]>_({ 'one': 1, 'two': 2, 'three': 3 }).keys().value();
 
diff --git a/lodash/lodash.d.ts b/lodash/lodash.d.ts
index 53729b9f5..e458fd0c7 100644
--- a/lodash/lodash.d.ts
+++ b/lodash/lodash.d.ts
@@ -6229,6 +6229,23 @@ declare module _ {
         isTypedArray(): boolean;
     }
 
+    //_.isUndefined
+    interface LoDashStatic {
+        /**
+         * Checks if value is undefined.
+         * @param value The value to check.
+         * @return Returns true if value is undefined, else false.
+         **/
+        isUndefined(value: any): boolean;
+    }
+
+    interface LoDashWrapperBase<T, TWrapper> {
+        /**
+         * see _.isUndefined
+         */
+        isUndefined(): boolean;
+    }
+
     //_.lt
     interface LoDashStatic {
         /**
@@ -7075,16 +7092,6 @@ declare module _ {
         isString(value?: any): boolean;
     }
 
-    //_.isUndefined
-    interface LoDashStatic {
-        /**
-        * Checks if value is undefined.
-        * @param value The value to check.
-        * @return True if the value is undefined, else false.
-        **/
-        isUndefined(value?: any): boolean;
-    }
-
     //_.keys
     interface LoDashStatic {
         /**