The COVID pandemic has made remote viewing of videos with your friends a major consideration for streaming services like Movies Anywhere, Hulu, and ahem Prime. The function is now working in Amazon̵
Both the broadcaster and guest must be subscribers to Amazon Prime (including Twitch Prime and its various extras) in order to start or access a Watch Party. All movies and TV shows on Amazon Prime Video can be viewed with your friends, but purchased or rented videos cannot, and neither can additional channels such as HBO. The library may be restricted for some parties where the host and viewer are in different countries. Streaming licenses are a headache this way.
To host a Twitch Stream Party, go to the Stream Manager on the Twitch Creator dashboard. In the Quick Actions area on the left, click the + button, then click Start Watch Party. In the left pane, click the new action. You can then browse the Amazon Prime content library and invite your friends. We could recommend The wonderful Mrs. Maisel?
Source: twitching over Engadget