diff --git a/lib/jekyll/convertible.rb b/lib/jekyll/convertible.rb
index e2564464..2ac9d0b4 100644
--- a/lib/jekyll/convertible.rb
+++ b/lib/jekyll/convertible.rb
@@ -87,8 +87,8 @@ module Jekyll
     # Convert this Convertible's data to a Hash suitable for use by Liquid.
     #
     # Returns the Hash representation of this Convertible.
-    def to_liquid
-      further_data = Hash[self.class::ATTRIBUTES_FOR_LIQUID.map { |attribute|
+    def to_liquid(attrs = nil)
+      further_data = Hash[(attrs || self.class::ATTRIBUTES_FOR_LIQUID).map { |attribute|
         [attribute, send(attribute)]
       }]
       data.deep_merge(further_data)