diff --git a/src/ol/format/wkt.js b/src/ol/format/wkt.js
index 819b4a1acd..dd625c15dd 100644
--- a/src/ol/format/wkt.js
+++ b/src/ol/format/wkt.js
@@ -394,6 +394,7 @@ ol.format.WKT.prototype.writeFeaturesText = function(features, opt_options) {
  *
  * @function
  * @param {ol.geom.Geometry} geometry Geometry.
+ * @param {olx.format.WriteOptions=} opt_options Write options.
  * @return {string} WKT string.
  * @api
  */