diff --git a/CHANGELOG.md b/CHANGELOG.md
index 194d812b8..fc3170b42 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -33,6 +33,12 @@
 
     *Josh Hunter*, *Jon Atack*
 
+*   Add test for ActionController:Parameter object params in sort_link to ensure
+    Ransack is handling the Rails 5 changes correctly. Follow-up to
+    [#644](https://github.com/activerecord-hackery/ransack/pull/644).
+
+    *Ryan Wood*
+
 *   Add failing tests to facilitate work on issue
     [#566](https://github.com/activerecord-hackery/ransack/issues/566)
     of passing boolean values to search scopes. PR
diff --git a/spec/ransack/helpers/form_helper_spec.rb b/spec/ransack/helpers/form_helper_spec.rb
index 67b7661b8..2c571f4e6 100644
--- a/spec/ransack/helpers/form_helper_spec.rb
+++ b/spec/ransack/helpers/form_helper_spec.rb
@@ -310,12 +310,13 @@ module Helpers
       end
 
       context 'view has existing parameters' do
-        before do
-          @controller.view_context.params[:exist] = 'existing'
-        end
+
         describe '#sort_link should not remove existing params' do
-          subject { @controller.view_context
-            .sort_link(
+
+          before { @controller.view_context.params[:exist] = 'existing' }
+
+          subject {
+            @controller.view_context.sort_link(
               Person.search(
                 { sorts: ['name desc'] },
                 search_key: 'people_search'
@@ -324,8 +325,33 @@ module Helpers
               controller: 'people'
             )
           }
+
           it { should match /exist\=existing/ }
         end
+
+        context 'using real ActionController Parameter object',
+          if: ::ActiveRecord::VERSION::MAJOR > 4 do
+
+          describe '#sort_link should include search params' do
+
+            subject { @controller.view_context.sort_link(Person.search, :name) }
+
+            let(:params) {
+              ActionController::Parameters
+              .new({ 'q' => { name_eq: 'TEST' }, controller: 'people' })
+            }
+
+            before { @controller.instance_variable_set(:@params, params) }
+
+            it {
+              should match(
+                /people\?q(%5B|\[)name_eq(%5D|\])=TEST&q(%5B|\[)s(%5D|\])
+                =name\+asc/x,
+              )
+            }
+          end
+
+        end
       end
 
       describe '#sort_link with hide order indicator set to true' do