Are Approvers automatically added as contacts to a request?

I thought that approvers were added as contacts to requests automatically, but an IT Partner has reported that occasionally the approvers are not the requestors of a given request and are not included as a contact on the request which causes their approval to fail. They were asking if it is possible to automatically add the approver as a contact on the request since their name is entered into the forms, but I thought this was already the case? Just wanted to confirm.