diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index e1d0c6c..e347853 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -1696,7 +1696,7 @@
                               cipher_suite, ciphersuite_info->name));
 
 #if defined(MBEDTLS_HAVE_TIME)
-    ssl->session_negotiate->start = time(NULL);
+    ssl->session_negotiate->start = mbedtls_time(NULL);
 #endif /* MBEDTLS_HAVE_TIME */
 
     /* ...