Button, accept mailing list. GDPR

Hi, we have got some email recipients on our list from before GDPR. We would like to send them a newsletter asking them if they would like to continue to receive newsletters from us. 

The idea was to include a button in the email they could click on to confirm, and then this information (their email) would end up on our list.

Is this possible? Would be great if this was possible without several steps sending them to a page to reenlist or they sending us an email.

Appreciate any takes on this:)

A better approach might be to send them an email first describing gdpr and then asking ”if you dont want to recieve any more mails, reply to this email”?

Then you dont have to deal with techy stuff. And you will definateley keep more of the users in the email list😊