One of the Google Home's best features is the ability to control playback of a Chromecast with voice commands. For example, you can ask "OK Google, play Gravity Falls on the living room TV" to start playing content without having another device nearby. Now the Fire TV can do that, but with Alexa devices.Amazon's Fire TV and Fire TV stick already have an Alexa button on the remote, which you can use to control media playback and open apps. A software update is rolling out to all Fire TV models that allows you to use all the same commands, but from another Alexa device (like an Echo or Echo Dot). You can use phrases like pause, play, resume, fast forward, and next episode.If your Fire TV finds that the update is available, it will install automatically when you reboot it (or after it is idle for 30 minutes). You can find more information at the source link below.

UPDATE: 2017/08/02 4:20am PDT BY CORBIN DAVENPORT

It looks like someone at Amazon jumped the gun a little and released the firmware changelog three weeks earlier before the feature was live. Now it's really official. Amazon says that the feature is rolling today in the US for all generations of Fire TV and Fire TV Stick, whereas smart TVs with Fire TV Edition will have it within the week. There's also a promised support for viewing smart home camera feeds on the Fire TV and 2nd gen Fire TV Stick, but that's said to be "coming soon."

Source: Fire TV Software Updates