Magento 2 : How to add additional fields to newsletter via graphQL

I have added new fields firstname and lastname in newsletter subscription by following this
https://www.thecoachsmb.com/magento-2-how-to-add-additional-fields-to-newsletter/

Now I need to add these fields in graphQL
How do i do it, Anyone please help

Currently i tried the default and it works fine

mutation {
  subscribeEmailToNewsletter(
    email: "[email protected]"
  ) {
    status
  }
}

I want to add firstname & lastname with this