Once you download and install, it will ask you to upgrade from your existing Office (2010) in my case to Office 2013. Upgrade is pretty simple. Just follow the steps.
I upgraded it and after the upgrade, see my Office icons.
New icons look like this for various applications.
Can you guess that these are all Metro Style?
YES. Entire Office 2013 is metro look. It will also have a Windows 8 metro UI soon and will support swipe and all that cool stuff.