diff --git a/spec/Tuurbo/Spreedly/TransactionSpec.php b/spec/Tuurbo/Spreedly/TransactionSpec.php
index a8e95a5..2f2769f 100644
--- a/spec/Tuurbo/Spreedly/TransactionSpec.php
+++ b/spec/Tuurbo/Spreedly/TransactionSpec.php
@@ -114,9 +114,7 @@ public function it_credits_a_purchase_with_no_amount_specified_and_with_extra_da
     public function it_captures_an_authorized_amount($client)
     {
         $data = [
-            'transaction' => [
-                'currency_code' => 'USD',
-            ],
+            'transaction' => [],
         ];
 
         $client->post('v1/transactions/'.self::TRANSACTION_TOKEN.'/capture.json', $data)
@@ -133,7 +131,6 @@ public function it_captures_a_specific_authorized_amount($client)
         $data = [
             'transaction' => [
                 'amount' => $amount,
-                'currency_code' => 'USD',
             ],
         ];
 
@@ -144,6 +141,25 @@ public function it_captures_a_specific_authorized_amount($client)
         $this->capture($amount)->shouldReturnAnInstanceOf('Tuurbo\Spreedly\Client');
     }
 
+    public function it_captures_a_specific_authorized_amount_and_currency($client)
+    {
+        $amount = 9.99;
+        $currencyCode = 'USD';
+
+        $data = [
+            'transaction' => [
+                'amount' => $amount,
+                'currency_code' => $currencyCode,
+            ],
+        ];
+
+        $client->post('v1/transactions/'.self::TRANSACTION_TOKEN.'/capture.json', $data)
+            ->shouldBeCalled()
+            ->willReturn($client);
+
+        $this->capture($amount, $currencyCode)->shouldReturnAnInstanceOf('Tuurbo\Spreedly\Client');
+    }
+
     public function it_completes_a_3ds2_transaction($client)
     {
         $client->post('v1/transactions/'.self::TRANSACTION_TOKEN.'/complete.json')
diff --git a/src/Transaction.php b/src/Transaction.php
index 4e00363..3f34e3e 100644
--- a/src/Transaction.php
+++ b/src/Transaction.php
@@ -151,14 +151,16 @@ public function transcript()
      *
      * @return \Tuurbo\Spreedly\Client
      */
-    public function capture($amount = null, $currency = 'USD', array $data = [])
+    public function capture($amount = null, $currency = null, array $data = [])
     {
         $params = [
-            'transaction' => [
-                'currency_code' => $currency,
-            ],
+            'transaction' => [],
         ];
 
+        if ($currency !== null) {
+            $params['transaction']['currency_code'] = $currency;
+        }
+
         if ($amount > 0) {
             $params['transaction']['amount'] = $amount;
         }