diff --git a/.github/workflows/release_prep.sh b/.github/workflows/release_prep.sh
index 81be757..5c01334 100755
--- a/.github/workflows/release_prep.sh
+++ b/.github/workflows/release_prep.sh
@@ -12,7 +12,7 @@ repository=${GITHUB_REPOSITORY#*/}
 directory="${repository}-${tag#v}"
 archive="${repository}-${tag}.tar.gz"
 
-git archive --format=tar --prefix=${directory}/ -o "${archive}" ${tag}
+git archive --format="tar.gz" --prefix=${directory}/ -o "${archive}" ${tag}
 
 # Replace hyphens with underscores in the repository name to match our Bazel
 # module naming conventions.
@@ -25,4 +25,4 @@ cat << EOF
 \`\`\`starlark
 bazel_dep(name = "${bazel_module_name}", version = "${tag}")
 \`\`\`
-EOF
\ No newline at end of file
+EOF