diff --git a/core/tests/Drupal/Tests/Traits/PHPUnit8Warnings.php b/core/tests/Drupal/Tests/Traits/PHPUnit8Warnings.php
index 5912ff048c..770e3be42f 100644
--- a/core/tests/Drupal/Tests/Traits/PHPUnit8Warnings.php
+++ b/core/tests/Drupal/Tests/Traits/PHPUnit8Warnings.php
@@ -23,6 +23,7 @@ trait PHPUnit8Warnings {
    * @var string[]
    */
   private static $ignoredWarnings = [
+    'expectExceptionMessageRegExp() is deprecated in PHPUnit 8 and will be removed in PHPUnit 9.',
     'Using assertContains() with string haystacks is deprecated and will not be supported in PHPUnit 9. Refactor your test to use assertStringContainsString() or assertStringContainsStringIgnoringCase() instead.',
     'Using assertNotContains() with string haystacks is deprecated and will not be supported in PHPUnit 9. Refactor your test to use assertStringNotContainsString() or assertStringNotContainsStringIgnoringCase() instead.',
     'assertArraySubset() is deprecated and will be removed in PHPUnit 9.',