Amazon hasn't confirmed if this will initially be in the US only - or if UK subscribers will also be able to reap the same high-resolution benefits.
Unlike Netflix, which charges extra for the privilege to stream in 4K, Amazon has said it will offer its content for free to their Prime subscribers.
Confirmed 4K content includes Amazon's original series Alpha House, Transparent and Mozart In The Jungle, while the Tony Bennett and Lady Gaga concert Cheek To Cheek will be available too. It's expected that more movies and TV programmes will be added over time.
More after the break
Amazon has said users will be required to update the Amazon Instant Video app on their TVs, which can be done at no added cost.