diff --git a/api/cpp/include/slint.h b/api/cpp/include/slint.h
index e6d04d786..9e9277b31 100644
--- a/api/cpp/include/slint.h
+++ b/api/cpp/include/slint.h
@@ -256,6 +256,13 @@ translate_from_bundle_with_plural(std::span<const char8_t *const> strs,
     return result;
 }
 
+template<typename Component>
+inline float get_resolved_default_font_size(const Component &component)
+{
+    ItemTreeRc item_tree_rc = (*component.self_weak.lock()).into_dyn();
+    return slint::cbindgen_private::slint_windowrc_resolved_default_font_size(&item_tree_rc);
+}
+
 } // namespace private_api
 
 #ifdef SLINT_FEATURE_GETTEXT
diff --git a/internal/compiler/generator/cpp.rs b/internal/compiler/generator/cpp.rs
index 6abaa9c58..3536ef0fe 100644
--- a/internal/compiler/generator/cpp.rs
+++ b/internal/compiler/generator/cpp.rs
@@ -3560,7 +3560,7 @@ fn compile_builtin_function_call(
             format!("{}.scale_factor()", access_window_field(ctx))
         }
         BuiltinFunction::GetWindowDefaultFontSize => {
-            format!("slint::cbindgen_private::slint_windowrc_resolved_default_font_size((*self_weak.lock()).into_dyn())")
+            format!("slint::private_api::get_resolved_default_font_size(*this)")
         }
         BuiltinFunction::AnimationTick => "slint::cbindgen_private::slint_animation_tick()".into(),
         BuiltinFunction::Debug => {