diff --git a/lib/SimpleSAML/Session.php b/lib/SimpleSAML/Session.php
index bc272c90116aa5d28b5d272205941b40d3ead8c9..91588e3881f9c75610783d5c0988df72ac213571 100644
--- a/lib/SimpleSAML/Session.php
+++ b/lib/SimpleSAML/Session.php
@@ -518,6 +518,20 @@ class SimpleSAML_Session {
 	public function isAuthenticated() {
 		return $this->authenticated;
 	}
+
+
+	/**
+	 * Retrieve the time the user was authenticated.
+	 *
+	 * @return int|NULL  The timestamp for when the user was authenticated. NULL if the user hasn't authenticated.
+	 */
+	public function getAuthnInstant() {
+		if (!$this->isAuthenticated()) {
+			return NULL;
+		}
+
+		return $this->sessionstarted;
+	}
 	
 	
 	// *** Attributes ***