diff --git a/sdk/include/host/pecoff.h b/sdk/include/host/pecoff.h
index 74104075fb6..f96982e910a 100644
--- a/sdk/include/host/pecoff.h
+++ b/sdk/include/host/pecoff.h
@@ -188,7 +188,7 @@ typedef struct _IMAGE_NT_HEADERS64
 {
   DWORD Signature;
   IMAGE_FILE_HEADER FileHeader;
-  IMAGE_OPTIONAL_HEADER32 OptionalHeader;
+  IMAGE_OPTIONAL_HEADER64 OptionalHeader;
 } IMAGE_NT_HEADERS64, *PIMAGE_NT_HEADERS64;
 
 #ifdef _TARGET_PE64