diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 0c43c79..a8a7119 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -768,6 +768,12 @@
                                 * but can be overwritten by the HRR. */
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
 
+#if defined(MBEDTLS_SSL_CLI_C)
+    int client_auth;           /*!< used to check if CertificateRequest is received
+                                    from server side. If CertificateReqeust is
+                                    received, Certificate and CertificateVerify
+                                    should be sent to server */
+#endif /* MBEDTLS_SSL_CLI_C */
     /*
      * State-local variables used during the processing
      * of a specific handshake state.