diff --git a/packages/typegen/src/util/derived.ts b/packages/typegen/src/util/derived.ts
index aa88cd9d7a..f293976327 100644
--- a/packages/typegen/src/util/derived.ts
+++ b/packages/typegen/src/util/derived.ts
@@ -155,5 +155,5 @@ export function getSimilarTypes (registry: Registry, definitions: Record<string,
     }
   }
 
-  return possibleTypes;
+  return [...new Set(possibleTypes)];
 }