diff --git a/LightJSonBuilder.cpp b/LightJSonBuilder.cpp
index 6401d87..5df878a 100644
--- a/LightJSonBuilder.cpp
+++ b/LightJSonBuilder.cpp
@@ -236,6 +236,19 @@ BOOL CLightJSonBuilder::AddObjectFormattedString(_In_z_ LPCSTR szNameA, _Printf_
   return AddObjectString(szNameA, (LPCSTR)cStrTempA, cStrTempA.GetLength());
 }
 
+BOOL CLightJSonBuilder::AddObjectFormattedStringV(_In_z_ LPCSTR szNameA, _Printf_format_string_ LPCSTR szFormatA, _In_ va_list argptr)
+{
+  CStringA cStrTempA;
+
+  MX_ASSERT(szFormatA != NULL);
+
+  if (cStrTempA.FormatV(szFormatA, argptr) == FALSE)
+    return FALSE;
+
+  //done
+  return AddObjectString(szNameA, (LPCSTR)cStrTempA, cStrTempA.GetLength());
+}
+
 BOOL CLightJSonBuilder::AddObjectString(_In_z_ LPCSTR szNameA, _In_ LPCWSTR szValueW, _In_opt_ SIZE_T nValueLen)
 {
   MX_ASSERT(szNameA != NULL);
@@ -286,6 +299,19 @@ BOOL CLightJSonBuilder::AddObjectFormattedString(_In_z_ LPCSTR szNameA, _Printf_
   return AddObjectString(szNameA, (LPCWSTR)cStrTempW, cStrTempW.GetLength());
 }
 
+BOOL CLightJSonBuilder::AddObjectFormattedStringV(_In_z_ LPCSTR szNameA, _Printf_format_string_ LPCWSTR szFormatW, _In_ va_list argptr)
+{
+  CStringW cStrTempW;
+
+  MX_ASSERT(szFormatW != NULL);
+
+  if (cStrTempW.FormatV(szFormatW, argptr) == FALSE)
+    return FALSE;
+
+  //done
+  return AddObjectString(szNameA, (LPCWSTR)cStrTempW, cStrTempW.GetLength());
+}
+
 BOOL CLightJSonBuilder::AddObjectString(_In_z_ LPCSTR szNameA, _In_ PUNICODE_STRING Value)
 {
   MX_ASSERT(szNameA != NULL);
@@ -540,6 +566,19 @@ BOOL CLightJSonBuilder::AddArrayFormattedString(_Printf_format_string_ LPCSTR sz
   return AddArrayString((LPCSTR)cStrTempA, cStrTempA.GetLength());
 }
 
+BOOL CLightJSonBuilder::AddArrayFormattedStringV(_Printf_format_string_ LPCSTR szFormatA, _In_ va_list argptr)
+{
+  CStringA cStrTempA;
+
+  MX_ASSERT(szFormatA != NULL);
+
+  if (cStrTempA.FormatV(szFormatA, argptr) == FALSE)
+    return FALSE;
+
+  //done
+  return AddArrayString((LPCSTR)cStrTempA, cStrTempA.GetLength());
+}
+
 BOOL CLightJSonBuilder::AddArrayString(_In_ LPCWSTR szValueW, _In_opt_ SIZE_T nValueLen)
 {
   MX_ASSERT(aNestedTypes.GetCount() > 0);
@@ -584,6 +623,19 @@ BOOL CLightJSonBuilder::AddArrayFormattedString(_Printf_format_string_ LPCWSTR s
   return AddArrayString((LPCWSTR)cStrTempW, cStrTempW.GetLength());
 }
 
+BOOL CLightJSonBuilder::AddArrayFormattedStringV(_Printf_format_string_ LPCWSTR szFormatW, _In_ va_list argptr)
+{
+  CStringW cStrTempW;
+
+  MX_ASSERT(szFormatW != NULL);
+
+  if (cStrTempW.FormatV(szFormatW, argptr) == FALSE)
+    return FALSE;
+
+  //done
+  return AddArrayString((LPCWSTR)cStrTempW, cStrTempW.GetLength());
+}
+
 BOOL CLightJSonBuilder::AddArrayLong(_In_ LONG nValue)
 {
   CHAR szTempBufA[64];
diff --git a/LightJSonBuilder.h b/LightJSonBuilder.h
index 9081086..7ee90ad 100644
--- a/LightJSonBuilder.h
+++ b/LightJSonBuilder.h
@@ -47,8 +47,10 @@ class CLightJSonBuilder : public CBaseMemObj, public CNonCopyableObj
   BOOL AddObjectBoolean(_In_z_ LPCSTR szNameA, _In_ BOOL bValue);
   BOOL AddObjectString(_In_z_ LPCSTR szNameA, _In_ LPCSTR szValueA, _In_opt_ SIZE_T nValueLen = (SIZE_T)-1);
   BOOL AddObjectFormattedString(_In_z_ LPCSTR szNameA, _Printf_format_string_ LPCSTR szFormatA, ...);
+  BOOL AddObjectFormattedStringV(_In_z_ LPCSTR szNameA, _Printf_format_string_ LPCSTR szFormatA, _In_ va_list argptr);
   BOOL AddObjectString(_In_z_ LPCSTR szNameA, _In_ LPCWSTR szValueW, _In_opt_ SIZE_T nValueLen = (SIZE_T)-1);
   BOOL AddObjectFormattedString(_In_z_ LPCSTR szNameA, _Printf_format_string_ LPCWSTR szFormatW, ...);
+  BOOL AddObjectFormattedStringV(_In_z_ LPCSTR szNameA, _Printf_format_string_ LPCWSTR szFormatW, _In_ va_list argptr);
   BOOL AddObjectString(_In_z_ LPCSTR szNameA, _In_ PUNICODE_STRING Value);
   BOOL AddObjectLong(_In_z_ LPCSTR szNameA, _In_ LONG nValue);
   BOOL AddObjectULong(_In_z_ LPCSTR szNameA, _In_ ULONG nValue, _In_opt_ BOOL bAsHexa = FALSE);
@@ -61,8 +63,10 @@ class CLightJSonBuilder : public CBaseMemObj, public CNonCopyableObj
   BOOL AddArrayBoolean(_In_ BOOL bValue);
   BOOL AddArrayString(_In_ LPCSTR szValueA, _In_opt_ SIZE_T nValueLen = (SIZE_T)-1);
   BOOL AddArrayFormattedString(_Printf_format_string_ LPCSTR szFormatA, ...);
+  BOOL AddArrayFormattedStringV(_Printf_format_string_ LPCSTR szFormatA, _In_ va_list argptr);
   BOOL AddArrayString(_In_ LPCWSTR szValueW, _In_opt_ SIZE_T nValueLen = (SIZE_T)-1);
   BOOL AddArrayFormattedString(_Printf_format_string_ LPCWSTR szFormatW, ...);
+  BOOL AddArrayFormattedStringV(_Printf_format_string_ LPCWSTR szFormatW, _In_ va_list argptr);
   BOOL AddArrayLong(_In_ LONG nValue);
   BOOL AddArrayULong(_In_ ULONG nValue, _In_opt_ BOOL bAsHexa = FALSE);
   //IMPORTANT: ECMA-262 Sec 8.5 states max number is 9007199254740990 so, if larger, it is recommended to store it as string