diff --git a/packages/Restoration/src/Rector/ClassConstFetch/MissingClassConstantReferenceToStringRector.php b/packages/Restoration/src/Rector/ClassConstFetch/MissingClassConstantReferenceToStringRector.php
new file mode 100644
index 000000000000..0e26ea910e0f
--- /dev/null
+++ b/packages/Restoration/src/Rector/ClassConstFetch/MissingClassConstantReferenceToStringRector.php
@@ -0,0 +1,73 @@
+<?php declare(strict_types=1);
+
+namespace Rector\Restoration\Rector\ClassConstFetch;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\ClassConstFetch;
+use PhpParser\Node\Scalar\String_;
+use Rector\NodeTypeResolver\ClassExistenceStaticHelper;
+use Rector\Rector\AbstractRector;
+use Rector\RectorDefinition\CodeSample;
+use Rector\RectorDefinition\RectorDefinition;
+
+/**
+ * @see \Rector\Restoration\Tests\Rector\ClassConstFetch\MissingClassConstantReferenceToStringRector\MissingClassConstantReferenceToStringRectorTest
+ */
+final class MissingClassConstantReferenceToStringRector extends AbstractRector
+{
+    public function getDefinition(): RectorDefinition
+    {
+        return new RectorDefinition('Convert missing class reference to string', [
+            new CodeSample(
+                <<<'PHP'
+class SomeClass
+{
+    public function run()
+    {
+        return NonExistingClass::class;
+    }
+}
+PHP
+                ,
+                <<<'PHP'
+class SomeClass
+{
+    public function run()
+    {
+        return 'NonExistingClass';
+    }
+}
+PHP
+            ),
+        ]);
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getNodeTypes(): array
+    {
+        return [ClassConstFetch::class];
+    }
+
+    /**
+     * @param ClassConstFetch $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        if (! $this->isName($node->name, 'class')) {
+            return null;
+        }
+
+        $referencedClass = $this->getName($node->class);
+        if ($referencedClass === null) {
+            return null;
+        }
+
+        if (ClassExistenceStaticHelper::doesClassLikeExist($referencedClass)) {
+            return null;
+        }
+
+        return new String_($referencedClass);
+    }
+}
diff --git a/packages/Restoration/tests/Rector/ClassConstFetch/MissingClassConstantReferenceToStringRector/Fixture/fixture.php.inc b/packages/Restoration/tests/Rector/ClassConstFetch/MissingClassConstantReferenceToStringRector/Fixture/fixture.php.inc
new file mode 100644
index 000000000000..1bc97fe39cf3
--- /dev/null
+++ b/packages/Restoration/tests/Rector/ClassConstFetch/MissingClassConstantReferenceToStringRector/Fixture/fixture.php.inc
@@ -0,0 +1,31 @@
+<?php
+
+namespace Rector\Restoration\Tests\Rector\ClassConstFetch\MissingClassConstantReferenceToStringRector\Fixture;
+
+use NonExistingClass;
+
+class SomeClass
+{
+    public function run()
+    {
+        return NonExistingClass::class;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Restoration\Tests\Rector\ClassConstFetch\MissingClassConstantReferenceToStringRector\Fixture;
+
+use NonExistingClass;
+
+class SomeClass
+{
+    public function run()
+    {
+        return 'NonExistingClass';
+    }
+}
+
+?>
diff --git a/packages/Restoration/tests/Rector/ClassConstFetch/MissingClassConstantReferenceToStringRector/MissingClassConstantReferenceToStringRectorTest.php b/packages/Restoration/tests/Rector/ClassConstFetch/MissingClassConstantReferenceToStringRector/MissingClassConstantReferenceToStringRectorTest.php
new file mode 100644
index 000000000000..67a6e6f7e0c9
--- /dev/null
+++ b/packages/Restoration/tests/Rector/ClassConstFetch/MissingClassConstantReferenceToStringRector/MissingClassConstantReferenceToStringRectorTest.php
@@ -0,0 +1,30 @@
+<?php declare(strict_types=1);
+
+namespace Rector\Restoration\Tests\Rector\ClassConstFetch\MissingClassConstantReferenceToStringRector;
+
+use Rector\Restoration\Rector\ClassConstFetch\MissingClassConstantReferenceToStringRector;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class MissingClassConstantReferenceToStringRectorTest extends AbstractRectorTestCase
+{
+    /**
+     * @dataProvider provideDataForTest()
+     */
+    public function test(string $file): void
+    {
+        $this->doTestFile($file);
+    }
+
+    /**
+     * @return string[]
+     */
+    public function provideDataForTest(): iterable
+    {
+        yield [__DIR__ . '/Fixture/fixture.php.inc'];
+    }
+
+    protected function getRectorClass(): string
+    {
+        return MissingClassConstantReferenceToStringRector::class;
+    }
+}