diff --git a/reactos/include/ndk/rtlfuncs.h b/reactos/include/ndk/rtlfuncs.h
index 9ddb0d03778..bcc2e13e202 100644
--- a/reactos/include/ndk/rtlfuncs.h
+++ b/reactos/include/ndk/rtlfuncs.h
@@ -3049,6 +3049,14 @@ RtlTimeFieldsToTime(
     PLARGE_INTEGER Time
 );
 
+NTSYSAPI
+VOID
+NTAPI
+RtlTimeToSecondsSince1970(
+    PLARGE_INTEGER Time,
+    OUT PULONG SecondsSince1970
+);
+
 NTSYSAPI
 VOID
 NTAPI