diff --git a/lib/searchkick/model.rb b/lib/searchkick/model.rb
index 7aaf4cd..7127d9f 100644
--- a/lib/searchkick/model.rb
+++ b/lib/searchkick/model.rb
@@ -22,21 +22,11 @@ module Searchkick
         raise ArgumentError, "Invalid value for callbacks"
       end
 
-      index_name =
-        if options[:index_name]
-          options[:index_name]
-        elsif options[:index_prefix].respond_to?(:call)
-          -> { [options[:index_prefix].call, model_name.plural, Searchkick.env, Searchkick.index_suffix].compact.join("_") }
-        else
-          [options.key?(:index_prefix) ? options[:index_prefix] : Searchkick.index_prefix, model_name.plural, Searchkick.env, Searchkick.index_suffix].compact.join("_")
-        end
-
       class_eval do
         cattr_reader :searchkick_options, :searchkick_klass
 
         class_variable_set :@@searchkick_options, options.dup
         class_variable_set :@@searchkick_klass, self
-        class_variable_set :@@searchkick_index, index_name
         class_variable_set :@@searchkick_index_cache, {}
 
         class << self
@@ -50,7 +40,7 @@ module Searchkick
           alias_method Searchkick.search_method_name, :searchkick_search if Searchkick.search_method_name
 
           def searchkick_index(name: nil)
-            index = name || class_variable_get(:@@searchkick_index)
+            index = name || searchkick_index_name
             index = index.call if index.respond_to?(:call)
             index_cache = class_variable_get(:@@searchkick_index_cache)
             index_cache[index] ||= Searchkick::Index.new(index, searchkick_options)
@@ -66,6 +56,19 @@ module Searchkick
           def searchkick_index_options
             searchkick_index.index_options
           end
+
+          def searchkick_index_name
+            @searchkick_index_name ||= begin
+              options = class_variable_get(:@@searchkick_options)
+              if options[:index_name]
+                options[:index_name]
+              elsif options[:index_prefix].respond_to?(:call)
+                -> { [options[:index_prefix].call, model_name.plural, Searchkick.env, Searchkick.index_suffix].compact.join("_") }
+              else
+                [options.key?(:index_prefix) ? options[:index_prefix] : Searchkick.index_prefix, model_name.plural, Searchkick.env, Searchkick.index_suffix].compact.join("_")
+              end
+            end
+          end
         end
 
         # always add callbacks, even when callbacks is false
--
libgit2 0.21.0