diff --git a/src/darker/git.py b/src/darker/git.py
index d259e8b04..328857294 100644
--- a/src/darker/git.py
+++ b/src/darker/git.py
@@ -33,6 +33,16 @@
 PRE_COMMIT_FROM_TO_REFS = ":PRE-COMMIT:"
 
 
+def git_rev_parse(revision: str, cwd: Path) -> str:
+    """Return the commit hash for the given revision
+
+    :param revision: The revision to get the commit hash for
+    :param cwd: The root of the Git repository
+
+    """
+    return _git_check_output_lines(["rev-parse", revision], cwd)[0]
+
+
 def git_rev_parse(revision: str, cwd: Path) -> str:
     """Return the commit hash for the given revision