diff --git a/lib/mongoid/criteria/includable.rb b/lib/mongoid/criteria/includable.rb
index 08edbfdbb14..89288351578 100644
--- a/lib/mongoid/criteria/includable.rb
+++ b/lib/mongoid/criteria/includable.rb
@@ -77,7 +77,7 @@ def inclusions=(value)
       #
       # @since 5.1.0
       def add_inclusion(_klass, relation)
-        metadata = get_inclusion_metadata(_klass, relation)
+        metadata = _klass.reflect_on_association(relation)
         raise Errors::InvalidIncludes.new(_klass, [ relation ]) unless metadata
         inclusions.push(metadata) unless inclusions.include?(metadata)
       end
@@ -116,7 +116,7 @@ def extract_nested_inclusion(_klass, relation)
           if _inclusion.is_a?(Array)
             extract_relations_list(association, _inclusion)
           else
-            add_inclusion(association, _inclusion)
+            add_inclusion(_klass.reflect_on_association(association).klass, _inclusion)
           end
         end
       end