USB hard drive as additional volume


I run Whonix via VirtualBox on an Ubuntu flash drive host system. As I do not have enough storage left on this flash drive I would like to connect an additional external hard drive.

My plan is to connect this external hard drive and add this one as a new virtual hard drive in virtual box.
I will then mount this new storage in my workstation.

Is it possible like this? Should I encrypt the external hard drive additionally?