sharepoint online – Disabling External Sharing and Item Level Permissions

We have a site that was shared with external emails but the Owner wants that reverted so no external access is allowed. I removed the external users from the Site Permissions but the question remains:

If I disable External Sharing on a Site Collection that has unique permissions on a Document, will that external user still be able to access the Document that has been explicitly shared with them in the past? Or will disabling external sharing lock them out of any document within that site regardless of the unique item level permissions?