How to manage Employee referral from current employer

Dear WSO - I hope you are doing well. I recently signed a contract to join another firm. As part of their background check. The agent requires a referral from my current employer that I am employed here. As I have not put in my notice of resignation yet and am on a visa I have a couple of questions:

1. How would you navigate this situation without facing repercussions?

2. What happens when HR receives an employment referral request for a current employee, who has not resigned yet?

3. Would HR inform my manager about the referral? and would they disclose the firm's name to my manager? The gist of the question is; is there any confidentiality between HR and the referral agency?

Thank you in advance!