Sending info from Contact 7 form to Mailchimp for auto-replies

Hi,
Would like to confirm if it’s possible and get info on how to set up the following:
We’d like to send the auto-reply email after a visitor submits a C7 form directly from Mailchimp. We have everything set up on the Mailchimp side: a drip campaign (2 emails a week apart) and a dedicated Mailchimp list just for the auto-replies.
Is it possible to sign up everyone that submits a contact from through our website to this special list (we don’t want to display a checkbox though to sign up — as we just would use this info for the auto-replies)?

Thanks in advance!