diff --git a/addons/web/static/src/js/openerpframework.js b/addons/web/static/src/js/openerpframework.js
index 99d11b58ca9..ca046543861 100644
--- a/addons/web/static/src/js/openerpframework.js
+++ b/addons/web/static/src/js/openerpframework.js
@@ -1128,7 +1128,7 @@ openerp.Model = openerp.Class.extend({
             kwargs = args;
             args = [];
         }
-        var call_kw = _.str.sprintf('/web/dataset/call_kw/%s/%s', this.name, method);
+        var call_kw = '/web/dataset/call_kw/' + this.name + '/' + method;
         return this.session().rpc(call_kw, {
             model: this.name,
             method: method,