diff --git a/wp-admin/custom-background.php b/wp-admin/custom-background.php
index 690638c8c5..e5666e71c4 100644
--- a/wp-admin/custom-background.php
+++ b/wp-admin/custom-background.php
@@ -205,8 +205,8 @@ if ( get_background_image() ) {
 	$background_image_thumb = esc_url( set_url_scheme( get_theme_mod( 'background_image_thumb', str_replace( '%', '%%', get_background_image() ) ) ) );
 	// background-image URL must be single quote, see below
 	$background_styles .= ' background-image: url(\'' . $background_image_thumb . '\');'
-		. ' background-repeat: ' . get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'background-repeat' ) ) . ';'
-		. ' background-position: top ' . get_theme_mod( 'background_position_x', get_theme_support( 'custom-background', 'background-position' ) );
+		. ' background-repeat: ' . get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'default-repeat' ) ) . ';'
+		. ' background-position: top ' . get_theme_mod( 'background_position_x', get_theme_support( 'custom-background', 'default-position-x' ) );
 }
 ?>
 <div id="custom-background-image" style="<?php echo $background_styles; ?>"><?php // must be double quote, see above ?>
@@ -276,15 +276,15 @@ if ( get_background_image() ) {
 <th scope="row"><?php _e( 'Position' ); ?></th>
 <td><fieldset><legend class="screen-reader-text"><span><?php _e( 'Background Position' ); ?></span></legend>
 <label>
-<input name="background-position-x" type="radio" value="left"<?php checked( 'left', get_theme_mod( 'background_position_x', get_theme_support( 'custom-background', 'background-position' ) ) ); ?> />
+<input name="background-position-x" type="radio" value="left"<?php checked( 'left', get_theme_mod( 'background_position_x', get_theme_support( 'custom-background', 'default-position-x' ) ) ); ?> />
 <?php _e('Left') ?>
 </label>
 <label>
-<input name="background-position-x" type="radio" value="center"<?php checked( 'center', get_theme_mod( 'background_position_x', get_theme_support( 'custom-background', 'background-position' ) ) ); ?> />
+<input name="background-position-x" type="radio" value="center"<?php checked( 'center', get_theme_mod( 'background_position_x', get_theme_support( 'custom-background', 'default-position-x' ) ) ); ?> />
 <?php _e('Center') ?>
 </label>
 <label>
-<input name="background-position-x" type="radio" value="right"<?php checked( 'right', get_theme_mod( 'background_position_x', get_theme_support( 'custom-background', 'background-position' ) ) ); ?> />
+<input name="background-position-x" type="radio" value="right"<?php checked( 'right', get_theme_mod( 'background_position_x', get_theme_support( 'custom-background', 'default-position-x' ) ) ); ?> />
 <?php _e('Right') ?>
 </label>
 </fieldset></td>
@@ -293,10 +293,10 @@ if ( get_background_image() ) {
 <tr valign="top">
 <th scope="row"><?php _e( 'Repeat' ); ?></th>
 <td><fieldset><legend class="screen-reader-text"><span><?php _e( 'Background Repeat' ); ?></span></legend>
-<label><input type="radio" name="background-repeat" value="no-repeat"<?php checked( 'no-repeat', get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'background-repeat' ) ) ); ?> /> <?php _e('No Repeat'); ?></label>
-	<label><input type="radio" name="background-repeat" value="repeat"<?php checked( 'repeat', get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'background-repeat' ) ) ); ?> /> <?php _e('Tile'); ?></label>
-	<label><input type="radio" name="background-repeat" value="repeat-x"<?php checked( 'repeat-x', get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'background-repeat' ) ) ); ?> /> <?php _e('Tile Horizontally'); ?></label>
-	<label><input type="radio" name="background-repeat" value="repeat-y"<?php checked( 'repeat-y', get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'background-repeat' ) ) ); ?> /> <?php _e('Tile Vertically'); ?></label>
+<label><input type="radio" name="background-repeat" value="no-repeat"<?php checked( 'no-repeat', get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'default-repeat' ) ) ); ?> /> <?php _e('No Repeat'); ?></label>
+	<label><input type="radio" name="background-repeat" value="repeat"<?php checked( 'repeat', get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'default-repeat' ) ) ); ?> /> <?php _e('Tile'); ?></label>
+	<label><input type="radio" name="background-repeat" value="repeat-x"<?php checked( 'repeat-x', get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'default-repeat' ) ) ); ?> /> <?php _e('Tile Horizontally'); ?></label>
+	<label><input type="radio" name="background-repeat" value="repeat-y"<?php checked( 'repeat-y', get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'default-repeat' ) ) ); ?> /> <?php _e('Tile Vertically'); ?></label>
 </fieldset></td>
 </tr>
 
@@ -304,11 +304,11 @@ if ( get_background_image() ) {
 <th scope="row"><?php _ex( 'Attachment', 'Background Attachment' ); ?></th>
 <td><fieldset><legend class="screen-reader-text"><span><?php _e( 'Background Attachment' ); ?></span></legend>
 <label>
-<input name="background-attachment" type="radio" value="scroll" <?php checked( 'scroll', get_theme_mod( 'background_attachment', get_theme_support( 'custom-background', 'background-attachment' ) ) ); ?> />
+<input name="background-attachment" type="radio" value="scroll" <?php checked( 'scroll', get_theme_mod( 'background_attachment', get_theme_support( 'custom-background', 'default-attachment' ) ) ); ?> />
 <?php _e( 'Scroll' ); ?>
 </label>
 <label>
-<input name="background-attachment" type="radio" value="fixed" <?php checked( 'fixed', get_theme_mod( 'background_attachment', get_theme_support( 'custom-background', 'background-attachment' ) ) ); ?> />
+<input name="background-attachment" type="radio" value="fixed" <?php checked( 'fixed', get_theme_mod( 'background_attachment', get_theme_support( 'custom-background', 'default-attachment' ) ) ); ?> />
 <?php _e( 'Fixed' ); ?>
 </label>
 </fieldset></td>
diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index 60f36d80da..e109125901 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -1280,17 +1280,17 @@ function _custom_background_cb() {
 	if ( $background ) {
 		$image = " background-image: url('$background');";
 
-		$repeat = get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'background-repeat' ) );
+		$repeat = get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'default-repeat' ) );
 		if ( ! in_array( $repeat, array( 'no-repeat', 'repeat-x', 'repeat-y', 'repeat' ) ) )
 			$repeat = 'repeat';
 		$repeat = " background-repeat: $repeat;";
 
-		$position = get_theme_mod( 'background_position_x', get_theme_support( 'custom-background', 'background-position' ) );
+		$position = get_theme_mod( 'background_position_x', get_theme_support( 'custom-background', 'default-position-x' ) );
 		if ( ! in_array( $position, array( 'center', 'right', 'left' ) ) )
 			$position = 'left';
 		$position = " background-position: top $position;";
 
-		$attachment = get_theme_mod( 'background_attachment', get_theme_support( 'custom-background', 'background-attachment' ) );
+		$attachment = get_theme_mod( 'background_attachment', get_theme_support( 'custom-background', 'default-attachment' ) );
 		if ( ! in_array( $attachment, array( 'fixed', 'scroll' ) ) )
 			$attachment = 'scroll';
 		$attachment = " background-attachment: $attachment;";
@@ -1483,9 +1483,9 @@ function add_theme_support( $feature ) {
 
 			$defaults = array(
 				'default-image'          => '',
-				'background-repeat'      => 'repeat',
-				'background-position'    => 'left',
-				'background-attachment'  => 'scroll',
+				'default-repeat'         => 'repeat',
+				'default-position-x'     => 'left',
+				'default-attachment'     => 'scroll',
 				'default-color'          => '',
 				'wp-head-callback'       => '_custom_background_cb',
 				'admin-head-callback'    => '',