There is no word yet on exactly which builds of Android this will appear on, and there is no precise launch date. But you might want to make sure that your Google+ profile picture makes you look good. Verified phone numbers listed in your Google account will be a part of this new feature by default. So before the ball drops in Times Square to signal the start of 2014, you should make sure that you're happy with your profile picture because this is the image of you that many people you call will remember you by whenever your name comes up in conversation.
source: +AttilaBodis via AndroidCentral