diff --git a/wp-includes/class-wp-customize-manager.php b/wp-includes/class-wp-customize-manager.php
index 86319753c1..207e442d7d 100644
--- a/wp-includes/class-wp-customize-manager.php
+++ b/wp-includes/class-wp-customize-manager.php
@@ -649,7 +649,6 @@ final class WP_Customize_Manager {
 			'default'           => get_theme_support( 'custom-background', 'default-color' ),
 			'sanitize_callback' => 'sanitize_hexcolor',
 			'theme_supports'    => 'custom-background',
-			'transport'         => 'postMessage',
 		) );
 
 		$this->add_control( new WP_Customize_Color_Control( $this, 'background_color', array(
@@ -716,6 +715,14 @@ final class WP_Customize_Manager {
 			),
 		) );
 
+		// If the theme is using the default background callback, we can update
+		// the background CSS using postMessage.
+		if ( get_theme_support( 'custom-background', 'wp-head-callback' ) === '_custom_background_cb' ) {
+			foreach ( array( 'color', 'image', 'position_x', 'repeat', 'attachment' ) as $prop ) {
+				$this->get_setting( 'background_' . $prop )->transport = 'postMessage';
+			}
+		}
+
 		/* Nav Menus */
 
 		$locations      = get_registered_nav_menus();
diff --git a/wp-includes/js/customize-preview.dev.js b/wp-includes/js/customize-preview.dev.js
index e6f8452daa..6d2540f90a 100644
--- a/wp-includes/js/customize-preview.dev.js
+++ b/wp-includes/js/customize-preview.dev.js
@@ -61,7 +61,7 @@
 		if ( ! api.settings )
 			return;
 
-		var preview, body;
+		var preview, bg;
 
 		preview = new api.Preview( window.location.href );
 
@@ -75,11 +75,36 @@
 				value.set.apply( value, args );
 		});
 
-		body = $(document.body);
-		// Auto update background color by default
-		api( 'background_color', function( value ) {
-			value.bind( function( to ) {
-				body.css( 'background-color', to ? '#' + to : '' );
+		/* Custom Backgrounds */
+		bg = $.map(['color', 'image', 'position_x', 'repeat', 'attachment'], function( prop ) {
+			return 'background_' + prop;
+		});
+
+		api.when.apply( api, bg ).done( function( color, image, position_x, repeat, attachment ) {
+			var style = $('#custom-background-css'),
+				update;
+
+			if ( ! style.length )
+				return;
+
+			update = function() {
+				var css = '';
+
+				if ( color() )
+					css += 'background-color: #' + color() + ';';
+
+				if ( image() ) {
+					css += 'background-image: url("' + image() + '");';
+					css += 'background-position: top ' + position_x() + ';';
+					css += 'background-repeat: ' + repeat() + ';';
+					css += 'background-position: top ' + attachment() + ';';
+				}
+
+				style.html( 'body.custom-background { ' + css + ' }' );
+			};
+
+			$.each( arguments, function() {
+				this.bind( update );
 			});
 		});
 	});
diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index 8ca4290781..eae3f4e207 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -1130,7 +1130,7 @@ function _custom_background_cb() {
 		$style .= $image . $repeat . $position . $attachment;
 	}
 ?>
-<style type="text/css">
+<style type="text/css" id="custom-background-css">
 body.custom-background { <?php echo trim( $style ); ?> }
 </style>
 <?php