diff --git a/include/spdlog/fmt/bundled/ostream.h b/include/spdlog/fmt/bundled/ostream.h
index 3bdb375b..f319f5fb 100644
--- a/include/spdlog/fmt/bundled/ostream.h
+++ b/include/spdlog/fmt/bundled/ostream.h
@@ -83,8 +83,8 @@ void write(std::ostream &os, Writer &w);
 }  // namespace internal
 
 // Formats a value.
-template <typename Char, typename ArgFormatter, typename T>
-void format_arg(BasicFormatter<Char, ArgFormatter> &f,
+template <typename Char, typename ArgFormatter_, typename T>
+void format_arg(BasicFormatter<Char, ArgFormatter_> &f,
                 const Char *&format_str, const T &value)
 {
     internal::MemoryBuffer<Char, internal::INLINE_BUFFER_SIZE> buffer;