First spotted by Android Police, the feature does not require an app update, but is only showing up to some users. Voice remote will show up as a floating button in the app; you can issue voice commands like "go back to my last channel" or "Play NBC," says the site. Apparently, you can also skip around in recorded shows and control the volume with your voice. Android Police notes that Google's already put up a support page, so it will likely show up for more people in time.