diff --git a/src/wp-includes/vars.php b/src/wp-includes/vars.php
index a5ce9ca29f..fbf83a0486 100644
--- a/src/wp-includes/vars.php
+++ b/src/wp-includes/vars.php
@@ -52,6 +52,7 @@ if ( isset($_SERVER['HTTP_USER_AGENT']) ) {
 		$is_lynx = true;
 	} elseif ( stripos($_SERVER['HTTP_USER_AGENT'], 'chrome') !== false ) {
 		if ( stripos( $_SERVER['HTTP_USER_AGENT'], 'chromeframe' ) !== false ) {
+			$is_admin = is_admin();
 			/**
 			 * Filter whether Google Chrome Frame should be used, if available.
 			 *
@@ -59,7 +60,7 @@ if ( isset($_SERVER['HTTP_USER_AGENT']) ) {
 			 *
 			 * @param bool $is_admin Whether to use the Google Chrome Frame. Default is the value of is_admin().
 			 */
-			if ( $is_chrome = apply_filters( 'use_google_chrome_frame', is_admin() ) )
+			if ( $is_chrome = apply_filters( 'use_google_chrome_frame', $is_admin ) )
 				header( 'X-UA-Compatible: chrome=1' );
 			$is_winIE = ! $is_chrome;
 		} else {