Modify request data after validation and before sending to controller

I am using Laravel's FormRequest for validation to make my code clean in controller and after validation, I want to add some data to request and then save it. So, I was just looking for a solution so that I do not have to add data to request in controller If just after validation in the same file there could be the extra function for modifying data and send to controller. It would have been better.

Thanks, In advance.

via Chebli Mohamed