diff --git a/MdePkg/Include/Library/UefiDriverEntryPoint.h b/MdePkg/Include/Library/UefiDriverEntryPoint.h
index ef9570ba04..2e520582ec 100644
--- a/MdePkg/Include/Library/UefiDriverEntryPoint.h
+++ b/MdePkg/Include/Library/UefiDriverEntryPoint.h
@@ -16,6 +16,11 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #ifndef __MODULE_ENTRY_POINT_H__
 #define __MODULE_ENTRY_POINT_H__
 
+///
+///Declare the PI Specification Revision that this driver requires to execute correctly.
+///
+extern CONST UINT32                   _gDxeRevision;
+
 ///
 /// Declare the EFI/UEFI Specification Revision to which this driver is implemented 
 ///