The agreement Google and Apple stitched together two months ago came to life this week.
From Variety's "Apple TV App Is Now Available on Chromecast With Google TV" posted Thursday
Plugging a notable gap in its streaming lineup, Google has added the Apple TV app — the only way to get the Apple TV Plus service — to its newest Chromecast device.
Starting Thursday, users with the $50 Chromecast with Google TVadapter will be able to access Apple TV. In addition, the Apple TV app is available on smart TVs from Sony and TCL that have the Google TV interface and Google says it will roll out to more Android TV-powered devices in the next few months...
To access the Apple TV app on the Chromecast with Google TV, users can navigate to the “Apps” tab or the apps row in the “For you” tab.
In the U.S., Google TV users can browse Apple TV Plus originals in the personalized recommendations and search results. Using Google Assistant, you can open the Apple TV app or play an Apple original title by speaking a command.
My take: Now you can watch Apple TV+ shows through the Apple TV app on the Chromecast with Google TV or you can watch Apple TV+ shows (and anything else that streams) through the Apple TV box. Got it?