diff --git a/Meta/Lagom/Tools/CodeGenerators/LibWeb/WrapperGenerator/IDLGenerators.cpp b/Meta/Lagom/Tools/CodeGenerators/LibWeb/WrapperGenerator/IDLGenerators.cpp
index f5fc02ecd3..280755f003 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibWeb/WrapperGenerator/IDLGenerators.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/LibWeb/WrapperGenerator/IDLGenerators.cpp
@@ -1050,7 +1050,7 @@ static void generate_to_cpp(SourceGenerator& generator, ParameterType& parameter
     @union_type@ @cpp_name@ = TRY(@js_name@@js_suffix@_to_variant(@js_name@@js_suffix@));
 )~~~");
             } else {
-                if (!optional_default_value.has_value()) {
+                if (!optional_default_value.has_value() || optional_default_value == "null"sv) {
                     union_generator.append(R"~~~(
     Optional<@union_type@> @cpp_name@;
     if (!@js_name@@js_suffix@.is_undefined())