Can assign same key to guest VMs which has already been assigned to Physical Host machine for activating Windows?

I am confuse to activate the Windows of Guest Machines which are hosted on MS Windows Server 2012 R2 Standard Edition. Same edition of Windows is installed on Guest VMs.

I know that License Keys are assigned to Physical Server for activating the Windows of Physical Server and One License of Windows Server 2012 R2 Standard Edition with two Physical CPU is applicable for only two guest VMs.

Please confirm that can we use same license key for activating Windows of Guest VMs however same key has already been used to physical host machine for activating its Windows.

Please help out……..

Principal.System Engineer