Virtual Maching Backup Question

When backing up virtual machines (Hyper-v), i have been told to put an agent on the Host machine and set up a backup shedule for the host machine. Then on the Virutal Machine, put an agent inside the machine as well so that you can do granular file recovery etc. But on that agent that is in the Virutal machine, do you also set up a backup regime for it, or is it handled (proxied) through the host machine?

Thanks