Different backgrounds for dual monitor setup

I have read and seen on videos that support for per-monitor backgrounds have been introduced natively in windows 8, but I cannot seem to find where to change the 2nd monitor background anywhere.

How can I set a different background for each monitor?

EDIT
Found the original blog post on MSDN

Right click your desktop, click Personalize and then on the bottom row of the Personalize window select Desktop Background, you will be able to set the individual backgrounds for your monitors there, as you can see in the example image below.

You can right-click a picture in the selection dialog and select on which monitor to show it.