diff --git a/README.rst b/README.rst
index 9e6a81e50..bde32b550 100644
--- a/README.rst
+++ b/README.rst
@@ -378,7 +378,8 @@ The following `command line arguments`_ can also be used to modify the defaults:
        versions that should be supported by Black's output. [default: per-file auto-
        detection]
 --formatter FORMATTER
-       [black\|none\|ruff] Formatter to use for reformatting code. [default: black]
+       [black\|none\|pyupgrade\|ruff] Formatter to use for reformatting code. [default:
+       black]
 
 To change default values for these options for a given project,
 add a ``[tool.darker]`` section to ``pyproject.toml`` in the project's root directory,