diff --git a/cibuildwheel/functools_cached_property_38.py b/cibuildwheel/functools_cached_property_38.py
index a83c40daf..879cdb620 100644
--- a/cibuildwheel/functools_cached_property_38.py
+++ b/cibuildwheel/functools_cached_property_38.py
@@ -21,7 +21,7 @@ def __set_name__(self, owner: type[Any], name: str) -> None:
         if self.attrname is None:
             self.attrname = name
         elif name != self.attrname:
-            msg = "Cannot assign the same cached_property to two different names ({self.attrname!r} and {name!r})."
+            msg = f"Cannot assign the same cached_property to two different names ({self.attrname!r} and {name!r})."
             raise TypeError(msg)
 
     @overload
diff --git a/cibuildwheel/logger.py b/cibuildwheel/logger.py
index 95bd97911..fe44e5f47 100644
--- a/cibuildwheel/logger.py
+++ b/cibuildwheel/logger.py
@@ -197,7 +197,7 @@ def build_description_from_identifier(identifier: str) -> str:
     elif python_interpreter == "pp":
         build_description += "PyPy"
     else:
-        msg = "unknown python {python_interpreter!r}"
+        msg = f"unknown python {python_interpreter!r}"
         raise Exception(msg)
 
     build_description += f" {python_version[0]}.{python_version[1:]} "