diff --git a/wp-includes/author-template.php b/wp-includes/author-template.php
index da24590b2e..017e448c39 100644
--- a/wp-includes/author-template.php
+++ b/wp-includes/author-template.php
@@ -2,7 +2,34 @@
 
 function get_the_author($idmode = '') {
 	global $authordata;
-	return apply_filters('the_author', $authordata->display_name);
+
+	switch ($idmode) {
+		case 'display_name':
+			$id = $authordata->display_name;
+			break;
+		case 'nickname':
+			$id = $authordata->nickname;
+			break;
+		case 'login':
+			$id = $authordata->user_login;
+			break;
+		case 'firstname':
+			$id = $authordata->user_firstname;
+			break;
+		case 'lastname':
+			$id = $authordata->user_lastname;
+			break;
+		case 'namefl':
+			$id = $authordata->user_firstname.' '.$authordata->user_lastname;
+			break;
+		case 'namelf':
+			$id = $authordata->user_lastname.' '.$authordata->user_firstname;
+			break;
+		default:
+			$id = $authordata->display_name;
+	}
+
+	return apply_filters('the_author', $id);
 }
 
 function the_author($idmode = '', $echo = true) {
@@ -239,4 +266,4 @@ function wp_list_authors($args = '') {
 	}
 }
 
-?>
\ No newline at end of file
+?>