diff --git a/src/Linq2GraphQL.Client/Common/CustomScalar.cs b/src/Linq2GraphQL.Client/Common/CustomScalar.cs
index 4a847f4f..988068eb 100644
--- a/src/Linq2GraphQL.Client/Common/CustomScalar.cs
+++ b/src/Linq2GraphQL.Client/Common/CustomScalar.cs
@@ -2,14 +2,14 @@
 {
     public class CustomScalar
     {
-        internal string InternalValue { get; set; }
+        internal object InternalValue { get; set; }
 
         public override string ToString()
         {
-            return InternalValue;
+            return InternalValue?.ToString();
         }
 
-        public virtual string Value
+        public virtual object Value
         {
             get { return InternalValue; }
 
diff --git a/src/Linq2GraphQL.Client/Converters/CustomScalarConverter.cs b/src/Linq2GraphQL.Client/Converters/CustomScalarConverter.cs
index 5a70f6bf..a5adf98b 100644
--- a/src/Linq2GraphQL.Client/Converters/CustomScalarConverter.cs
+++ b/src/Linq2GraphQL.Client/Converters/CustomScalarConverter.cs
@@ -27,7 +27,7 @@ public override TScalar Read(ref Utf8JsonReader reader, Type typeToConvert, Json
 
         public override void Write(Utf8JsonWriter writer, TScalar value, JsonSerializerOptions options)
         {
-            writer.WriteStringValue(value.InternalValue);
+            writer.WriteStringValue(value.InternalValue?.ToString());
         }
 
     }
diff --git a/test/Linq2GraphQL.TestClientNullable/ExtendedScalars/MacAddress.cs b/test/Linq2GraphQL.TestClientNullable/ExtendedScalars/MacAddress.cs
index 228fa230..1831ff18 100644
--- a/test/Linq2GraphQL.TestClientNullable/ExtendedScalars/MacAddress.cs
+++ b/test/Linq2GraphQL.TestClientNullable/ExtendedScalars/MacAddress.cs
@@ -16,7 +16,10 @@ public MacAddress(string value)
             Value = value;
         }
 
-        public override string Value
+
+
+
+        public override object Value
         {
             get
             {