diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index f990243..c141e8a 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -218,6 +218,10 @@
     mbedtls_x509_crl *sni_ca_crl;       /*!< trusted CAs CRLs from SNI      */
 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
+#if defined(MBEDTLS_SSL_ASYNC_PRIVATE_C)
+    void *p_async_operation_ctx;        /*!< asynchronous operation context */
+#endif /* MBEDTLS_SSL_ASYNC_PRIVATE_C */
+
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     unsigned int out_msg_seq;           /*!<  Outgoing handshake sequence number */
     unsigned int in_msg_seq;            /*!<  Incoming handshake sequence number */