Does a Hyper-V Replica server require additional licensing

I realize that with Windows Server 2012 Standard, I need 2 server licenses to run a Hyper-V host with 4 virtual machines (you get 2 VM’s per license). 

I am thinking about purchasing another identical physical server and configuring it as a Hyper-V Replica Server. 

If I want to replicate my existing host and VM’s to another Hyper-V Replica server, do I need any additional licensing?  I wasn't sure since this server would only be used if my primary Host would happed to go down.

Thanks in advance.

Nate