Can I have a blank field input which also contains a selection?

Hi! I'd like to have an input field when creating a content type, like an article, which asks the user to provide information, like author, by selecting an existing entry or adding a new entry. For example, if someone was credited as author before, their name would appear in a select box. If not, the user has the option to provide a new author's name which, upon submission, will then store that author's name in the preselected box.

This is convenient, but also important for referencing names (so if Jill Smith becomes Jill Andrews, we can change her name in one place and it will reflect throughout the site) and also for keeping consistencies (so that Thomas McDonald isn't also called Tom Mcdonald, Thomas M, and so on).

I can think of a bunch of ways I want to use this (for Venue information on Events, for Organizer information on Events, for Author information on Articles, etc.), and I'm wondering if this can be done. I haven't found the exact solution online.

Can I add this to a content type?

Thanks!