diff --git a/lib/thinking_sphinx/active_record.rb b/lib/thinking_sphinx/active_record.rb
index 2bc8e2e1a..50b5dd565 100644
--- a/lib/thinking_sphinx/active_record.rb
+++ b/lib/thinking_sphinx/active_record.rb
@@ -75,6 +75,7 @@ def define_index(&block)
             return unless ThinkingSphinx.define_indexes?
             
             self.sphinx_indexes ||= []
+            self.sphinx_facets  ||= []
             index = ThinkingSphinx::Index::Builder.generate(self, &block)
             
             self.sphinx_indexes << index