O365 migrated mailbox accessing shared mailboxes on-prem

Hello Experts. If i migrate a user from on prem exchange 2013, with outlook 2016, to O365, will the user still be able to acces shared mailboxes that he has access to that are on-prem, or do we need to migrate the shared mailboxes first to O365? Then how will on-prem users connect to the shared mailboxes on 365? We will have a hybrid scenario in place for this. Please let me know, and thanks in advance.