diff --git a/lib/xlsx/xlsx.js b/lib/xlsx/xlsx.js
index db687013b..f9bb4253c 100644
--- a/lib/xlsx/xlsx.js
+++ b/lib/xlsx/xlsx.js
@@ -46,8 +46,6 @@ var XLSX = module.exports = function (workbook) {
 };
 
 
-var getTheme1Xml = utils.readModuleFile(require.resolve('./xml/theme1.xml'));
-
 XLSX.RelType = require('./rel-type');
 
 
@@ -265,7 +263,7 @@ XLSX.prototype = {
   },
 
   addThemes: function (zip) {
-    return getTheme1Xml
+    return utils.readModuleFile(require.resolve('./xml/theme1.xml'));
       .then(function (data) {
         zip.append(data, {name: 'xl/theme/theme1.xml'});
         return zip;