diff --git a/rules-tests/TypeDeclaration/Rector/ClassMethod/StrictStringParamConcatRector/Fixture/skip_inner_closure.php.inc b/rules-tests/TypeDeclaration/Rector/ClassMethod/StrictStringParamConcatRector/Fixture/skip_inner_closure.php.inc
deleted file mode 100644
index 6e32c3bd472..00000000000
--- a/rules-tests/TypeDeclaration/Rector/ClassMethod/StrictStringParamConcatRector/Fixture/skip_inner_closure.php.inc
+++ /dev/null
@@ -1,17 +0,0 @@
-<?php
-
-namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\StrictStringParamConcatRector\Fixture;
-
-final class SkipInnerClosure
-{
-    public function resolve($item)
-    {
-        $result = $item * 100;
-
-        function ($item) {
-            return $item . ' world';
-        };
-
-        return $result;
-    }
-}
diff --git a/rules-tests/TypeDeclaration/Rector/ClassMethod/StrictStringParamConcatRector/Fixture/with_inner_closure.php.inc b/rules-tests/TypeDeclaration/Rector/ClassMethod/StrictStringParamConcatRector/Fixture/with_inner_closure.php.inc
new file mode 100644
index 00000000000..6e15c876672
--- /dev/null
+++ b/rules-tests/TypeDeclaration/Rector/ClassMethod/StrictStringParamConcatRector/Fixture/with_inner_closure.php.inc
@@ -0,0 +1,39 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\StrictStringParamConcatRector\Fixture;
+
+final class WithInnerClosure
+{
+    public function resolve($item)
+    {
+        $result = $item * 100;
+
+        function ($item) {
+            return $item . ' world';
+        };
+
+        return $result;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\StrictStringParamConcatRector\Fixture;
+
+final class WithInnerClosure
+{
+    public function resolve($item)
+    {
+        $result = $item * 100;
+
+        function (string $item) {
+            return $item . ' world';
+        };
+
+        return $result;
+    }
+}
+
+?>
diff --git a/rules/TypeDeclaration/Rector/ClassMethod/StrictStringParamConcatRector.php b/rules/TypeDeclaration/Rector/ClassMethod/StrictStringParamConcatRector.php
index 17afaf99692..dbb163492d5 100644
--- a/rules/TypeDeclaration/Rector/ClassMethod/StrictStringParamConcatRector.php
+++ b/rules/TypeDeclaration/Rector/ClassMethod/StrictStringParamConcatRector.php
@@ -7,6 +7,7 @@
 use PhpParser\Node;
 use PhpParser\Node\Expr;
 use PhpParser\Node\Expr\AssignOp\Concat;
+use PhpParser\Node\Expr\Closure;
 use PhpParser\Node\Expr\Variable;
 use PhpParser\Node\FunctionLike;
 use PhpParser\Node\Identifier;
@@ -62,11 +63,11 @@ public function resolve(string $item)
      */
     public function getNodeTypes(): array
     {
-        return [ClassMethod::class, Function_::class];
+        return [ClassMethod::class, Function_::class, Closure::class];
     }
 
     /**
-     * @param ClassMethod|Function_ $node
+     * @param ClassMethod|Function_|Closure $node
      */
     public function refactor(Node $node): ?Node
     {
@@ -96,7 +97,7 @@ public function refactor(Node $node): ?Node
         return null;
     }
 
-    private function isParamConcatted(Param $param, ClassMethod|Function_ $functionLike): bool
+    private function isParamConcatted(Param $param, ClassMethod|Function_|Closure $functionLike): bool
     {
         if ($functionLike->stmts === null) {
             return false;