diff --git a/src/wp-includes/rest-api.php b/src/wp-includes/rest-api.php
index 06bb9f9..7b537e0 100644
--- a/src/wp-includes/rest-api.php
+++ b/src/wp-includes/rest-api.php
@@ -438,8 +438,9 @@ function rest_get_server() {
  * Ensures request arguments are a request object (for consistency).
  *
  * @since 4.4.0
+ * @since 4.9.0 Accept string argument for the request path.
  *
- * @param array|WP_REST_Request $request Request to check.
+ * @param array|string|WP_REST_Request $request Request to check.
  * @return WP_REST_Request REST request instance.
  */
 function rest_ensure_request( $request ) {
@@ -447,6 +448,10 @@ function rest_ensure_request( $request ) {
 		return $request;
 	}
 
+	if ( is_string( $request ) ) {
+		return new WP_REST_Request( 'GET', $request );
+	}
+
 	return new WP_REST_Request( 'GET', '', $request );
 }