diff --git a/lib/wicked_pdf/wicked_pdf_helper/assets.rb b/lib/wicked_pdf/wicked_pdf_helper/assets.rb
index c7e4db8c..3d551798 100644
--- a/lib/wicked_pdf/wicked_pdf_helper/assets.rb
+++ b/lib/wicked_pdf/wicked_pdf_helper/assets.rb
@@ -68,7 +68,12 @@ def asset_pathname(source)
           end
         else
           asset = find_asset(source)
-          asset ? asset.pathname : File.join(Rails.public_path, source)
+          if asset
+            # older versions need pathname, Sprockets 4 supports only filename
+            asset.respond_to?(:filename) ? asset.filename : asset.pathname
+          else
+            File.join(Rails.public_path, source)
+          end
         end
       end