diff --git a/flight/core/Dispatcher.php b/flight/core/Dispatcher.php
index 53f193fc..2e21c867 100644
--- a/flight/core/Dispatcher.php
+++ b/flight/core/Dispatcher.php
@@ -299,6 +299,10 @@ public function execute($callback, array $params = [])
         $this->verifyValidFunction($callback);
 
         if (is_string($callback)) {
+            if (function_exists($callback)) {
+                return $callback(...$params);
+            }
+
             $callback = $this->parseStringClassAndMethod($callback);
         }
 
diff --git a/tests/DispatcherTest.php b/tests/DispatcherTest.php
index af8569ec..be6a04d9 100644
--- a/tests/DispatcherTest.php
+++ b/tests/DispatcherTest.php
@@ -168,6 +168,11 @@ public function testInvalidCallableString(): void
         $this->dispatcher->execute('nonexistentGlobalFunction');
     }
 
+    public function testExecuteGlobalFunctionString(): void
+    {
+        $this->assertSame('HELLO', $this->dispatcher->execute('strtoupper', ['hello']));
+    }
+
     // It will be useful for executing instance Controller methods statically
     public function testCanExecuteAnNonStaticMethodStatically(): void
     {