diff --git a/include/flatbuffers/idl.h b/include/flatbuffers/idl.h
index b564b1b27..cd70cb612 100644
--- a/include/flatbuffers/idl.h
+++ b/include/flatbuffers/idl.h
@@ -297,7 +297,8 @@ struct FieldDef : public Definition {
         flexbuffer(false),
         presence(kDefault),
         nested_flatbuffer(nullptr),
-        padding(0) {}
+        padding(0),
+        sibling_union_field(nullptr){}
 
   Offset<reflection::Field> Serialize(FlatBufferBuilder *builder, uint16_t id,
                                       const Parser &parser) const;
@@ -342,6 +343,12 @@ struct FieldDef : public Definition {
 
   StructDef *nested_flatbuffer;  // This field contains nested FlatBuffer data.
   size_t padding;                // Bytes to always pad after this field.
+
+  // sibling_union_field is always set to nullptr. The only exception is
+  // when FieldDef is a union field or an union type field. Therefore,
+  // sibling_union_field on a union field points to the union type field
+  // and vice-versa.
+  FieldDef *sibling_union_field;
 };
 
 struct StructDef : public Definition {
diff --git a/src/idl_parser.cpp b/src/idl_parser.cpp
index 9650cc9dd..360f0c744 100644
--- a/src/idl_parser.cpp
+++ b/src/idl_parser.cpp
@@ -970,6 +970,14 @@ CheckedError Parser::ParseField(StructDef &struct_def) {
   FieldDef *field;
   ECHECK(AddField(struct_def, name, type, &field));
 
+  if (typefield) {
+     // We preserve the relation between the typefield
+     // and field, so we can easily map it in the code
+     // generators.
+     typefield->sibling_union_field = field;
+     field->sibling_union_field = typefield;
+  }
+
   if (token_ == '=') {
     NEXT();
     ECHECK(ParseSingleValue(&field->name, field->value, true));