diff --git a/reactos/dll/win32/shell32/shell32.cpp b/reactos/dll/win32/shell32/shell32.cpp
index 2ef621af55f..4eb18473dd9 100644
--- a/reactos/dll/win32/shell32/shell32.cpp
+++ b/reactos/dll/win32/shell32/shell32.cpp
@@ -25,6 +25,45 @@
 
 WINE_DEFAULT_DEBUG_CHANNEL(shell);
 
+/*
+ * Implemented
+ */
+EXTERN_C LPWSTR
+WINAPI
+AddCommasW(DWORD lValue, LPWSTR lpNumber)
+{
+    WCHAR szValue[MAX_PATH], szSeparator[8 + 1];
+    NUMBERFMTW numFormat;
+
+    GetLocaleInfoW(LOCALE_USER_DEFAULT,
+                   LOCALE_STHOUSAND,
+                   szSeparator,
+                   ARRAYSIZE(szSeparator));
+
+    numFormat.NumDigits     = 0;
+    numFormat.LeadingZero   = 0;
+    numFormat.Grouping      = 0; // FIXME! Use GetLocaleInfoW with LOCALE_SGROUPING and interpret the result.
+    numFormat.lpDecimalSep  = szSeparator;
+    numFormat.lpThousandSep = szSeparator;
+    numFormat.NegativeOrder = 0;
+
+    swprintf(szValue, L"%llu", lValue);
+    //_ultow(lValue, szValue, 10);
+
+    if (GetNumberFormatW(LOCALE_USER_DEFAULT,
+                         0,
+                         szValue,
+                         &numFormat,
+                         lpNumber,
+                         wcslen(lpNumber)) != 0)
+    {
+        return lpNumber;
+    }
+
+    wcscpy(lpNumber, szValue);
+    return lpNumber;
+}
+
 /**************************************************************************
  * Default ClassFactory types
  */
diff --git a/reactos/dll/win32/shell32/stubs.cpp b/reactos/dll/win32/shell32/stubs.cpp
index df6f7fa1373..0a2e12a4d4e 100644
--- a/reactos/dll/win32/shell32/stubs.cpp
+++ b/reactos/dll/win32/shell32/stubs.cpp
@@ -14,19 +14,6 @@
 
 WINE_DEFAULT_DEBUG_CHANNEL(shell);
 
-/*
- * Unimplemented
- */
-EXTERN_C LPWSTR
-WINAPI
-AddCommasW(DWORD dwUnknown, LPWSTR lpNumber)
-{
-    LPCWSTR lpRetBuf = L"0";
-
-    FIXME("AddCommasW() stub\n");
-    return const_cast<LPWSTR>(lpRetBuf);
-}
-
 /*
  * Unimplemented
  */