diff --git a/cms/djangoapps/contentstore/views/preview.py b/cms/djangoapps/contentstore/views/preview.py
index fa55cb2c24..202927bdfb 100644
--- a/cms/djangoapps/contentstore/views/preview.py
+++ b/cms/djangoapps/contentstore/views/preview.py
@@ -165,7 +165,7 @@ def load_preview_module(request, preview_id, descriptor):
 
 def get_preview_html(request, descriptor, idx):
     module = load_preview_module(request, str(idx), descriptor)
-    return module.runtime.render(module, None, "student_view")
+    return module.runtime.render(module, None, "student_view").content
 
 
 def get_module_previews(request, descriptor):