diff --git a/src/Translator.php b/src/Translator.php
index 8494fcb0..bc7bbbf0 100644
--- a/src/Translator.php
+++ b/src/Translator.php
@@ -148,8 +148,8 @@ public function translate($message, $count = NULL, $parameters = [], $domain = N
 			return $message; // what now?
 		}
 
-		if (!is_string($message)) {
-			throw new \Kdyby\Translation\InvalidArgumentException(sprintf('Message id must be a string, %s was given', gettype($message)));
+		if (!is_string($message) && !is_int($message)) {
+			throw new \Kdyby\Translation\InvalidArgumentException(sprintf('Message id must be a string or integer, %s was given', gettype($message)));
 		}
 
 		if (Strings::startsWith($message, '//')) {
@@ -182,8 +182,8 @@ public function translate($message, $count = NULL, $parameters = [], $domain = N
 	 */
 	public function trans($message, array $parameters = [], $domain = NULL, $locale = NULL)
 	{
-		if (!is_string($message)) {
-			throw new \Kdyby\Translation\InvalidArgumentException(sprintf('Message id must be a string, %s was given', gettype($message)));
+		if (!is_string($message) && !is_int($message)) {
+			throw new \Kdyby\Translation\InvalidArgumentException(sprintf('Message id must be a string or integer, %s was given', gettype($message)));
 		}
 
 		if ($domain === NULL) {
@@ -207,8 +207,8 @@ public function trans($message, array $parameters = [], $domain = NULL, $locale
 	 */
 	public function transChoice($message, $number, array $parameters = [], $domain = NULL, $locale = NULL)
 	{
-		if (!is_string($message)) {
-			throw new \Kdyby\Translation\InvalidArgumentException(sprintf('Message id must be a string, %s was given', gettype($message)));
+		if (!is_string($message) && !is_int($message)) {
+			throw new \Kdyby\Translation\InvalidArgumentException(sprintf('Message id must be a string or integer, %s was given', gettype($message)));
 		}
 
 		if ($domain === NULL) {