diff --git a/include/mbedtls/threading.h b/include/mbedtls/threading.h
index 1047f8f..fae96c2 100644
--- a/include/mbedtls/threading.h
+++ b/include/mbedtls/threading.h
@@ -21,6 +21,7 @@
  */
 #ifndef MBEDTLS_THREADING_H
 #define MBEDTLS_THREADING_H
+#include "mbedtls/private_access.h"
 
 #if !defined(MBEDTLS_CONFIG_FILE)
 #include "mbedtls/config.h"
@@ -41,11 +42,11 @@
 #include <pthread.h>
 typedef struct mbedtls_threading_mutex_t
 {
-    pthread_mutex_t mutex;
+    pthread_mutex_t MBEDTLS_PRIVATE(mutex);
     /* is_valid is 0 after a failed init or a free, and nonzero after a
      * successful init. This field is not considered part of the public
      * API of Mbed TLS and may change without notice. */
-    char is_valid;
+    char MBEDTLS_PRIVATE(is_valid);
 } mbedtls_threading_mutex_t;
 #endif