diff --git a/wp-content/themes/twentyeleven/functions.php b/wp-content/themes/twentyeleven/functions.php
index 31f80e4cc..cf3c627f9 100644
--- a/wp-content/themes/twentyeleven/functions.php
+++ b/wp-content/themes/twentyeleven/functions.php
@@ -109,12 +109,12 @@ function twentyeleven_setup() {
 	// This theme uses Featured Images (also known as post thumbnails) for per-post/per-page Custom Header images
 	add_theme_support( 'post-thumbnails' );
 
-	// The next four constants set how twentyeleven supports custom headers
+	// The next four constants set how Twenty Eleven supports custom headers.
 
 	// The default header text color
 	define( 'HEADER_TEXTCOLOR', '000' );
 
-	// By leaving empty, we default to random image rotation
+	// By leaving empty, we allow for random image rotation.
 	define( 'HEADER_IMAGE', '' );
 
 	// The height and width of your custom header.
@@ -131,6 +131,9 @@ function twentyeleven_setup() {
 	add_image_size( 'large-feature', HEADER_IMAGE_WIDTH, HEADER_IMAGE_HEIGHT, true ); // Used for large feature (header) images
 	add_image_size( 'small-feature', 500, 300 ); // Used for featured posts if a large-feature doesn't exist
 
+	// Turn on random header image rotation by default.
+	add_theme_support( 'custom-header', array( 'random-default' => true ) );
+
 	// Add a way for the custom header to be styled in the admin panel that controls
 	// custom headers. See twentyeleven_admin_header_style(), below.
 	add_custom_image_header( 'twentyeleven_header_style', 'twentyeleven_admin_header_style', 'twentyeleven_admin_header_image' );
diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index a5d6150a2..78d97395b 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -1460,8 +1460,15 @@ function get_random_header_image() {
 
 	if ( 'random-uploaded-image' == $header_image_mod )
 		$headers = get_uploaded_header_images();
-	elseif ( ! empty( $_wp_default_headers ) )
-		$headers = $_wp_default_headers;
+	elseif ( ! empty( $_wp_default_headers ) ) {
+		if ( 'random-default-image' == $header_image_mod ) {
+			$headers = $_wp_default_headers;
+		} else {
+			$is_random = get_theme_support( 'custom-header' );
+			if ( isset( $is_random[ 0 ] ) && !empty( $is_random[ 0 ][ 'random-default' ] ) )
+				$headers = $_wp_default_headers;
+		}
+	}
 
 	if ( empty( $headers ) )
 		return '';
@@ -1476,7 +1483,8 @@ function get_random_header_image() {
  * Check if random header image is in use.
  *
  * Always true if user expressly chooses the option in Appearance > Header.
- * Also true if theme has multiple header images registered and no specific header image is chosen.
+ * Also true if theme has multiple header images registered, no specific header image
+ * is chosen, and theme turns on random headers with add_theme_support().
  *
  * @since 3.2.0
  * @uses HEADER_IMAGE
@@ -1494,7 +1502,7 @@ function is_random_header_image( $type = 'any' ) {
 	} else {
 		if ( "random-$type-image" == $header_image_mod )
 			return true;
-		elseif ( 'default' == $type && empty( $header_image_mod ) && '' != get_random_header_image()  )
+		elseif ( 'default' == $type && empty( $header_image_mod ) && '' != get_random_header_image() )
 			return true;
 	}
 
@@ -1557,7 +1565,11 @@ function add_custom_image_header( $header_callback, $admin_header_callback, $adm
 	if ( ! empty( $header_callback ) )
 		add_action('wp_head', $header_callback);
 
-	add_theme_support( 'custom-header', array( 'callback' => $header_callback ) );
+	$support = array( 'callback' => $header_callback );
+	$theme_support = get_theme_support( 'custom-header' );
+	if ( ! empty( $theme_support ) && is_array( $theme_support[ 0 ] ) )
+		$support = array_merge( $theme_support[ 0 ], $support );
+	add_theme_support( 'custom-header',  $support );
 	add_theme_support( 'custom-header-uploads' );
 
 	if ( ! is_admin() )