diff --git a/rules-tests/TypeDeclarationDocblocks/Rector/Class_/AddReturnDocblockDataProviderRector/Fixture/keep_string_type_simple.php.inc b/rules-tests/TypeDeclarationDocblocks/Rector/Class_/AddReturnDocblockDataProviderRector/Fixture/keep_string_type_simple.php.inc
new file mode 100644
index 00000000000..934ba63e8ec
--- /dev/null
+++ b/rules-tests/TypeDeclarationDocblocks/Rector/Class_/AddReturnDocblockDataProviderRector/Fixture/keep_string_type_simple.php.inc
@@ -0,0 +1,54 @@
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\Class_\AddReturnDocblockDataProviderRector\Fixture;
+
+use PHPStan\Type\ObjectType;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Rector\Tests\NodeTypeResolver\PerNodeTypeResolver\VariableTypeResolver\Source\AnotherType;
+
+final class KeepStringTypeSimple extends TestCase
+{
+    #[DataProvider('provideData')]
+    public function testSomething()
+    {
+    }
+
+    public static function provideData(): \Iterator
+    {
+        $anotherTypeObjectType = new ObjectType(AnotherType::class);
+        yield [__DIR__ . '/Fixture/new_class.php.inc', 1, $anotherTypeObjectType];
+        yield [__DIR__ . '/Fixture/argument_typehint.php.inc', 1, $anotherTypeObjectType];
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\Class_\AddReturnDocblockDataProviderRector\Fixture;
+
+use PHPStan\Type\ObjectType;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Rector\Tests\NodeTypeResolver\PerNodeTypeResolver\VariableTypeResolver\Source\AnotherType;
+
+final class KeepStringTypeSimple extends TestCase
+{
+    #[DataProvider('provideData')]
+    public function testSomething()
+    {
+    }
+
+    /**
+     * @return \Iterator<array<int, (int | \PHPStan\Type\ObjectType | string)>>
+     */
+    public static function provideData(): \Iterator
+    {
+        $anotherTypeObjectType = new ObjectType(AnotherType::class);
+        yield [__DIR__ . '/Fixture/new_class.php.inc', 1, $anotherTypeObjectType];
+        yield [__DIR__ . '/Fixture/argument_typehint.php.inc', 1, $anotherTypeObjectType];
+    }
+}
+
+?>
diff --git a/rules/Privatization/TypeManipulator/TypeNormalizer.php b/rules/Privatization/TypeManipulator/TypeNormalizer.php
index af3bbe8e7e6..e29c0c16df5 100644
--- a/rules/Privatization/TypeManipulator/TypeNormalizer.php
+++ b/rules/Privatization/TypeManipulator/TypeNormalizer.php
@@ -4,6 +4,8 @@
 
 namespace Rector\Privatization\TypeManipulator;
 
+use PHPStan\Type\Accessory\AccessoryLiteralStringType;
+use PHPStan\Type\Accessory\AccessoryNonFalsyStringType;
 use PHPStan\Type\ArrayType;
 use PHPStan\Type\BooleanType;
 use PHPStan\Type\Constant\ConstantArrayType;
@@ -55,6 +57,10 @@ public function generalizeConstantBoolTypes(Type $type): Type
     public function generalizeConstantTypes(Type $type): Type
     {
         return TypeTraverser::map($type, function (Type $type, callable $traverseCallback): Type {
+            if ($type instanceof AccessoryNonFalsyStringType || $type instanceof AccessoryLiteralStringType) {
+                return new StringType();
+            }
+
             if ($type instanceof ConstantBooleanType) {
                 return new BooleanType();
             }