diff --git a/src/_pytest/reports.py b/src/_pytest/reports.py
index 9e61d7def..f23ee0831 100644
--- a/src/_pytest/reports.py
+++ b/src/_pytest/reports.py
@@ -209,7 +209,7 @@ class BaseReport:
 
         fail(
             "pytest_report_teststatus() hook (from a plugin) returned "
-            "an invalid verbose value: {verbose!r}.\nExpected either a string "
+            f"an invalid verbose value: {verbose!r}.\nExpected either a string "
             "or a tuple of (word, markup)."
         )