diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index eed4413..04c3098 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -389,6 +389,9 @@
     unsigned char _pms_ecdhe_psk[4 + MBEDTLS_ECP_MAX_BYTES
                                    + MBEDTLS_PSK_MAX_LEN];     /* RFC 5489 2 */
 #endif
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+    unsigned char _pms_ecjpake[32];     /* Thread spec: SHA-256 output */
+#endif
 };
 
 #define MBEDTLS_PREMASTER_SIZE     sizeof( union mbedtls_ssl_premaster_secret )