Form - Combo Box with option that auto-adds new input to source table

Hi,

I have a Form "Deals" to allow user to create a new records to a table called "Deals"

One input is "Seller" which specifies the name of a company and the list is generated via table "Company"

Currently, the user given a combo box has the option to choose multiple company names from the list...however, if a user has a company name that is not currently available on the list...I'd like them to have the option to input a new company name into the Form. Then this new company name should automatically add itself to the "Company" table and therefore it will become automatically available in the Form "Seller" list option going forward....simply, I'd like the user to be able to add a new company name to the list and be restricted to the Form, without having to go into back-end and update the "Company" table.

Thank you.