Upgrade From Whs 2011 To Windows 8

Hi,
I currently have WHS 2011 as my home server. I'd like to switch to Windows 8 instead.

Does anybody know if it is possible to do an upgrade directly from WHS 2011 to Windows 8?

Or do I have to install another OS (XP in my case) first before upgrading?

Regards
/ Lasse T.