diff --git a/lib/stripe_mock/request_handlers/subscriptions.rb b/lib/stripe_mock/request_handlers/subscriptions.rb
index ee588fbd3..b0b6248e8 100644
--- a/lib/stripe_mock/request_handlers/subscriptions.rb
+++ b/lib/stripe_mock/request_handlers/subscriptions.rb
@@ -97,7 +97,7 @@ def create_subscription(route, method_url, params, headers)
           customer[:default_source] = new_card[:id]
         end
 
-        allowed_params = %w(customer application_fee_percent coupon items metadata plan quantity source tax_percent trial_end trial_period_days current_period_start created prorate billing_cycle_anchor billing days_until_due idempotency_key enable_incomplete_payments cancel_at_period_end default_tax_rates payment_behavior pending_invoice_item_interval default_payment_method collection_method off_session trial_from_plan proration_behavior backdate_start_date transfer_data expand automatic_tax)
+        allowed_params = %w(customer application_fee_percent coupon items metadata plan quantity source tax_percent trial_end trial_period_days current_period_start created prorate billing_cycle_anchor billing days_until_due idempotency_key enable_incomplete_payments cancel_at_period_end default_tax_rates payment_behavior pending_invoice_item_interval default_payment_method collection_method off_session trial_from_plan proration_behavior backdate_start_date transfer_data expand automatic_tax pay_immediately)
         unknown_params = params.keys - allowed_params.map(&:to_sym)
         if unknown_params.length > 0
           raise Stripe::InvalidRequestError.new("Received unknown parameter: #{unknown_params.join}", unknown_params.first.to_s, http_status: 400)