diff --git a/booking.emails.inc b/booking.emails.inc
index 84ce5d4..9a41ce7 100644
--- a/booking.emails.inc
+++ b/booking.emails.inc
@@ -42,7 +42,7 @@ function _booking_registration_email($nid, $balance_payment, $manual = false) {
 	$params['subject'] = $subject;
 
 	//apply a theme to the HTML body of the email
-	$html_body = theme('booking_htmlmail_template', 
+	$html_body = theme('booking_htmlmail_registration_mail', 
 		array(
 			'module' => 'booking',
 			'key' => 'registration_mail',