diff --git a/include/fmt/core.h b/include/fmt/core.h
index 8d36f75f..f0815206 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -2208,7 +2208,7 @@ template <typename Context> class value {
   FMT_CONSTEXPR value(const T& x FMT_BUILTIN) {
     static_assert(std::is_same<C, char_type>::value,
                   "mixing character types is disallowed");
-    auto sv = to_string_view(x);
+    auto sv = detail::to_string_view(x);
     string.data = sv.data();
     string.size = sv.size();
   }
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 318ce814..96aa20ed 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -3815,7 +3815,7 @@ FMT_CONSTEXPR auto write(OutputIt out, basic_string_view<Char> value)
 template <typename Char, typename OutputIt, typename T,
           FMT_ENABLE_IF(has_to_string_view<T>::value)>
 constexpr auto write(OutputIt out, const T& value) -> OutputIt {
-  return write<Char>(out, to_string_view(value));
+  return write<Char>(out, detail::to_string_view(value));
 }
 
 // FMT_ENABLE_IF() condition separated to workaround an MSVC bug.