diff --git a/elasticsearch-model/lib/elasticsearch/model/adapters/multiple.rb b/elasticsearch-model/lib/elasticsearch/model/adapters/multiple.rb
index b4df631f4..80c34c856 100644
--- a/elasticsearch-model/lib/elasticsearch/model/adapters/multiple.rb
+++ b/elasticsearch-model/lib/elasticsearch/model/adapters/multiple.rb
@@ -28,6 +28,17 @@ module Multiple
         Adapter.register self, lambda { |klass| klass.is_a? Multimodel }
 
         module Records
+
+          def self.included(base)
+            base.extend(ClassMethods)
+          end
+
+          module ClassMethods
+            def __clear_types!
+              @@__types = nil
+            end
+          end
+
           # Returns a collection of model instances, possibly of different classes (ActiveRecord, Mongoid, ...)
           #
           # @note The order of results in the Elasticsearch response is preserved
diff --git a/elasticsearch-model/lib/elasticsearch/model/multimodel.rb b/elasticsearch-model/lib/elasticsearch/model/multimodel.rb
index 2c2306274..5af7d0ce0 100644
--- a/elasticsearch-model/lib/elasticsearch/model/multimodel.rb
+++ b/elasticsearch-model/lib/elasticsearch/model/multimodel.rb
@@ -48,7 +48,12 @@ def self.all
       # Adds a model to the registry
       #
       def add(klass)
-        @models << klass
+        if i = @models.index { |_class| _class.name == klass.name }
+          @models[i] = klass
+          Model::Multiple.__clear_types!
+        else
+          @models << klass
+        end
       end
 
       # Returns a copy of the registered models