// OtherController::fancy($name, $color) will be executed
public function myAction($name)
{
    $response = $this->forward(
        'App\Controller\OtherController::fancy',
        array(
              'name'  => $name,
            'color' => 'green',
        )
    );
    // ... further modify the response or return it directly
    return $response;
}