diff --git a/core/lib/Drupal/Core/Session/AccountInterface.php b/core/lib/Drupal/Core/Session/AccountInterface.php
index 1cf82dcb63..f85c29710a 100644
--- a/core/lib/Drupal/Core/Session/AccountInterface.php
+++ b/core/lib/Drupal/Core/Session/AccountInterface.php
@@ -148,8 +148,9 @@ public function getDisplayName();
   /**
    * Returns the email address of this account.
    *
-   * @return string
-   *   The email address.
+   * @return string|NULL
+   *   The email address, or NULL if the account is anonymous or the user does
+   *   not have an email address.
    */
   public function getEmail();