diff --git a/src/wp-admin/includes/class-custom-background.php b/src/wp-admin/includes/class-custom-background.php
index d8500d8570405..8027c6a2ce95e 100644
--- a/src/wp-admin/includes/class-custom-background.php
+++ b/src/wp-admin/includes/class-custom-background.php
@@ -288,7 +288,7 @@ public function admin_page() {
 			$background_styles = '';
 			$bgcolor           = get_background_color();
 			if ( $bgcolor ) {
-				$background_styles .= 'background-color: #' . $bgcolor . ';';
+				$background_styles .= 'background-color: ' . maybe_hash_hex_color( $bgcolor ) . ';';
 			}
 
 			$background_image_thumb = get_background_image();
diff --git a/src/wp-includes/theme.php b/src/wp-includes/theme.php
index 1a9b2479ad7e2..5b6824b4a1073 100644
--- a/src/wp-includes/theme.php
+++ b/src/wp-includes/theme.php
@@ -1893,7 +1893,7 @@ function _custom_background_cb() {
 		return;
 	}
 
-	$style = $color ? "background-color: #$color;" : '';
+	$style = $color ? 'background-color: ' . maybe_hash_hex_color( $color ) . ';' : '';
 
 	if ( $background ) {
 		$image = ' background-image: url("' . sanitize_url( $background ) . '");';