diff --git a/app/controllers/checkout_controller.rb b/app/controllers/checkout_controller.rb
index e68b083351..fdc98e55f4 100644
--- a/app/controllers/checkout_controller.rb
+++ b/app/controllers/checkout_controller.rb
@@ -80,8 +80,6 @@ class CheckoutController < BaseController
 
     @order.customer.touch :terms_and_conditions_accepted_at
 
-    return true if redirect_to_payment_gateway
-
     # Redeem VINE voucher
     vine_voucher_redeemer = Vine::VoucherRedeemerService.new(order: @order)
     unless vine_voucher_redeemer.redeem
@@ -94,6 +92,9 @@ class CheckoutController < BaseController
       return false
       # rubocop:enable Rails/DeprecatedActiveModelErrorsMethods
     end
+
+    return true if redirect_to_payment_gateway
+
     @order.process_payments!
     @order.confirm!
     BackorderJob.check_stock(@order)
diff --git a/spec/controllers/checkout_controller_spec.rb b/spec/controllers/checkout_controller_spec.rb
index 165264f47e..ea6da1b012 100644
--- a/spec/controllers/checkout_controller_spec.rb
+++ b/spec/controllers/checkout_controller_spec.rb
@@ -625,14 +625,30 @@ RSpec.describe CheckoutController do
             expect(flash[:error]).to match "There was an error while trying to redeem your voucher"
           end
         end
+
+        context "when an external payment gateway is used" do
+          before do
+            expect(payment_method).to receive(:external_gateway?) { true }
+            expect(payment_method).to receive(:external_payment_url) { "https://example.com/pay" }
+            mock_payment_method_fetcher(payment_method)
+          end
+
+          it "redeems the voucher and redirect to the payment gateway's URL" do
+            expect(vine_voucher_redeemer).to receive(:redeem).and_return(true)
+
+            put(:update, params:)
+
+            expect(response.body).to match("https://example.com/pay").and match("redirect")
+            expect(order.reload.state).to eq "confirmation"
+          end
+        end
       end
 
       context "when an external payment gateway is used" do
         before do
-          expect(Checkout::PaymentMethodFetcher).
-            to receive_message_chain(:new, :call) { payment_method }
           expect(payment_method).to receive(:external_gateway?) { true }
           expect(payment_method).to receive(:external_payment_url) { "https://example.com/pay" }
+          mock_payment_method_fetcher(payment_method)
         end
 
         describe "confirming the order" do
@@ -693,4 +709,9 @@ RSpec.describe CheckoutController do
       [{ "url" => "/checkout/details", "operation" => "redirectTo" }].to_json
     )
   end
+
+  def mock_payment_method_fetcher(payment_method)
+    payment_method_fetcher = instance_double(Checkout::PaymentMethodFetcher, call: payment_method)
+    expect(Checkout::PaymentMethodFetcher).to receive(:new).and_return(payment_method_fetcher)
+  end
 end