diff --git a/lib/ci/pipeline_creation/inputs/string_input.rb b/lib/ci/pipeline_creation/inputs/string_input.rb
index bb5ca29efc8..7ea9746ade5 100644
--- a/lib/ci/pipeline_creation/inputs/string_input.rb
+++ b/lib/ci/pipeline_creation/inputs/string_input.rb
@@ -54,7 +54,7 @@ module Ci
 
         override :coerced_value
         def coerced_value(value)
-          super.to_s
+          value.to_s
         end
       end
     end
diff --git a/spec/lib/ci/pipeline_creation/inputs/spec_inputs_spec.rb b/spec/lib/ci/pipeline_creation/inputs/spec_inputs_spec.rb
index 6d6d97d9e43..18e0fd3a25f 100644
--- a/spec/lib/ci/pipeline_creation/inputs/spec_inputs_spec.rb
+++ b/spec/lib/ci/pipeline_creation/inputs/spec_inputs_spec.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'fast_spec_helper'
+require 'oj'
 require_relative Rails.root.join('lib/ci/pipeline_creation/inputs/spec_inputs.rb')
 
 RSpec.describe Ci::PipelineCreation::Inputs::SpecInputs, feature_category: :pipeline_composition do
diff --git a/spec/lib/gitlab/ci/config/interpolation/inputs_spec.rb b/spec/lib/gitlab/ci/config/interpolation/inputs_spec.rb
index ba23a6c8df7..c8dd2ad00a8 100644
--- a/spec/lib/gitlab/ci/config/interpolation/inputs_spec.rb
+++ b/spec/lib/gitlab/ci/config/interpolation/inputs_spec.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'fast_spec_helper'
+require 'oj'
 require_relative Rails.root.join('lib/gitlab/ci/config/interpolation/inputs.rb')
 
 RSpec.describe Gitlab::Ci::Config::Interpolation::Inputs, feature_category: :pipeline_composition do
@@ -195,6 +196,16 @@ RSpec.describe Gitlab::Ci::Config::Interpolation::Inputs, feature_category: :pip
           expect(inputs.to_hash).to eq(foo: 'bar')
         end
       end
+
+      context 'when a hash value is passed as string' do
+        let(:specs) { { test_input: { type: 'string' } } }
+        let(:args) { { test_input: '{"key": "value"}' } }
+
+        it 'is valid and behaves like an unparsed string' do
+          expect(inputs).to be_valid
+          expect(inputs.to_hash).to eq(test_input: '{"key": "value"}')
+        end
+      end
     end
 
     describe 'number validation' do
diff --git a/spec/requests/api/ci/pipelines_spec.rb b/spec/requests/api/ci/pipelines_spec.rb
index c1025f34ca2..4fd0615d58f 100644
--- a/spec/requests/api/ci/pipelines_spec.rb
+++ b/spec/requests/api/ci/pipelines_spec.rb
@@ -889,10 +889,14 @@ RSpec.describe API::Ci::Pipelines, feature_category: :continuous_integration do
             { 'Content-Type' => 'application/x-www-form-urlencoded' }
           end
 
+          let(:transformed_values) do
+            inputs.transform_values { |value| value.is_a?(String) ? value : value.to_json }
+          end
+
           subject(:post_request) do
             post api("/projects/#{project.id}/pipeline", user),
               headers: headers,
-              params: { ref: project.default_branch, inputs: inputs.transform_values(&:to_json) }
+              params: { ref: project.default_branch, inputs: transformed_values }
           end
 
           it_behaves_like 'creating a succesful pipeline'
diff --git a/spec/requests/api/ci/triggers_spec.rb b/spec/requests/api/ci/triggers_spec.rb
index 330e271d3a1..0311666f3ce 100644
--- a/spec/requests/api/ci/triggers_spec.rb
+++ b/spec/requests/api/ci/triggers_spec.rb
@@ -237,10 +237,14 @@ RSpec.describe API::Ci::Triggers, feature_category: :pipeline_composition do
             { 'Content-Type' => 'application/x-www-form-urlencoded' }
           end
 
+          let(:transformed_values) do
+            inputs.transform_values { |value| value.is_a?(String) ? value : value.to_json }
+          end
+
           subject(:post_request) do
             post api("/projects/#{project.id}/ref/master/trigger/pipeline?token=#{token}"),
               headers: headers,
-              params: { ref: 'refs/heads/other-branch', inputs: inputs.transform_values(&:to_json) }
+              params: { ref: 'refs/heads/other-branch', inputs: transformed_values }
           end
 
           it_behaves_like 'creating a succesful pipeline'