diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 3b5aadb..b1f0c90 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -2276,4 +2276,8 @@
                                        const unsigned char *end );
 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
 
+int mbedtls_ssl_tls13_get_sig_alg_from_pk( mbedtls_ssl_context *ssl,
+                                           mbedtls_pk_context *own_key,
+                                           uint16_t *algorithm );
+
 #endif /* ssl_misc.h */