diff --git a/src/recast.ts b/src/recast.ts
index a0f1b19..0dfe5b6 100644
--- a/src/recast.ts
+++ b/src/recast.ts
@@ -1,5 +1,5 @@
 import { InvalidRequest } from './exceptions';
-import { Callable, integer, Integer } from './interface';
+import { BaseModel, Callable, integer, Integer } from './interface';
 
 type primitive = string | number | boolean | bigint | integer | object;
 
@@ -70,7 +70,7 @@ export const transformValue = (
         });
     } else {
         // if type is plain object, we leave it as is
-        if (Object.is(cls, Object)) {
+        if (Object.is(cls, Object) || cls.prototype instanceof BaseModel) {
             return value;
         }
         if (
diff --git a/tests/data/sample-model.ts b/tests/data/sample-model.ts
index aed0cec..b8680db 100644
--- a/tests/data/sample-model.ts
+++ b/tests/data/sample-model.ts
@@ -200,6 +200,25 @@ export class DeeperDict extends BaseModel {
     deepestList?: Optional<Array<integer>>;
 }
 
+export class TagsModel extends BaseModel {
+    ['constructor']: typeof TagsModel;
+
+    @Expose({ name: 'Tags' })
+    @Transform((value, obj) => transformValue(Tag, 'tags', value, obj, [Set]), {
+        toClassOnly: true,
+    })
+    tags?: Optional<Set<Tag>>;
+}
+
+class Tag extends BaseModel {
+    ['constructor']: typeof Tag;
+
+    @Expose({ name: 'Name' })
+    name: string;
+    @Expose({ name: 'Value' })
+    value: string;
+}
+
 export class SimpleResourceModel extends BaseModel {
     ['constructor']: typeof SimpleResourceModel;
 
diff --git a/tests/lib/recast.test.ts b/tests/lib/recast.test.ts
index 5fca35c..f55b987 100644
--- a/tests/lib/recast.test.ts
+++ b/tests/lib/recast.test.ts
@@ -3,6 +3,7 @@ import { transformValue, recastPrimitive } from '~/recast';
 import {
     ResourceModel as ComplexResourceModel,
     SimpleResourceModel,
+    TagsModel,
 } from '../data/sample-model';
 
 describe('when recasting objects', () => {
@@ -105,15 +106,29 @@ describe('when recasting objects', () => {
         );
     });
 
+    test('recast set type - array with unique items', () => {
+        const payload = {
+            Tags: [{ key: 'name', value: 'value' }],
+        };
+        const expected = {
+            Tags: new Set([{ key: 'name', value: 'value' }]),
+        };
+        const model = TagsModel.deserialize(payload);
+        const serialized = JSON.parse(JSON.stringify(model));
+        expect(serialized).toMatchObject(expected);
+        expect(TagsModel.deserialize(serialized).serialize()).toMatchObject(expected);
+    });
+
     test('recast object invalid sub type', () => {
+        class InvalidClass {}
         const k = 'key';
         const v = { a: 1, b: 2 };
         const recastObject = () => {
-            transformValue(SimpleResourceModel, k, v, {});
+            transformValue(InvalidClass, k, v, {});
         };
         expect(recastObject).toThrow(exceptions.InvalidRequest);
         expect(recastObject).toThrow(
-            `Unsupported type: ${typeof v} [${SimpleResourceModel.name}] for ${k}`
+            `Unsupported type: ${typeof v} [${InvalidClass.name}] for ${k}`
         );
     });