diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index abb7a14..1b827ac 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -1485,4 +1485,51 @@
 }
 #endif /* MBEDTLS_ECDH_C */
 
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+int mbedtls_ssl_session_set_hostname( mbedtls_ssl_session *ssl,
+                                      const char *hostname )
+{
+    /* Initialize to suppress unnecessary compiler warning */
+    size_t hostname_len = 0;
+
+    /* Check if new hostname is valid before
+     * making any change to current one */
+    if( hostname != NULL )
+    {
+        hostname_len = strlen( hostname );
+
+        if( hostname_len > MBEDTLS_SSL_MAX_HOST_NAME_LEN )
+            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+    }
+
+    /* Now it's clear that we will overwrite the old hostname,
+     * so we can free it safely */
+
+    if( ssl->hostname != NULL )
+    {
+        mbedtls_platform_zeroize( ssl->hostname, strlen( ssl->hostname ) );
+        mbedtls_free( ssl->hostname );
+    }
+
+    /* Passing NULL as hostname shall clear the old one */
+
+    if( hostname == NULL )
+    {
+        ssl->hostname = NULL;
+    }
+    else
+    {
+        ssl->hostname = mbedtls_calloc( 1, hostname_len + 1 );
+        if( ssl->hostname == NULL )
+            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
+
+        memcpy( ssl->hostname, hostname, hostname_len );
+
+        ssl->hostname[hostname_len] = '\0';
+        ssl->hostname_len = hostname_len;
+    }
+
+    return( 0 );
+}
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
 #endif /* MBEDTLS_SSL_TLS_C && MBEDTLS_SSL_PROTO_TLS1_3 */