You don't need to install the games onto your own console, although that's now an option for many of them too.
Here then is everything you need to know about PlayStation Now.
How does it work?
PS Now is a cloud-based service much like Netflix or Spotify, but for gaming. It hosts a wide collection of back catalogue and recent PS3 and PS4 titles (almost 600 games are available). You can access them at your leisure, all through a PS Now app on your PlayStation 4.
It uses technology acquired when Sony bought cloud gaming company Gakai, which allows you to play games that are not hosted on your own local console, but on massive servers elsewhere.
In a similar fashion to Nvidia's GeForce Now service, the video of the game streams over the internet to the display you are using, with controller commands and your actions sent the other way. This happens instantly, so the effect is similar to running a disc at home.
Some PS4 games on the platform are now available to download too, which work exactly like their equivalents bought from the digital PlayStation Store and are run from your console rather than remotely. You will need the hard drive space to install them and they only work while you continue to subscribe, but you will notice better graphical resolution and no lag or latency issues.
Do PS Now games look and play exactly like the games we can play on the PS4 directly?
Streamed video is in 720p rather than 1080p. That doesn't matter so much for PS3 titles that were originally created in that resolution but a dip in detail and picture sharpness will be more noticeable for the PS4 line-up.
There are also reports of slight lag and latency issues when playing some of the faster, more controller demanding games. Latency is basically the time it takes between you pressing a button on the controller and seeing the results appear on screen. Because the controller response has to travel over the internet to a PlayStation Now service, be understood, then the video has to travel back over the internet to your console and TV, there is an unavoidable lag that wouldn't occur if you were playing the same game locally.
However, great strides have been made in ensuring the latency is as low as possible and you would be hard pressed to notice it on most games. The vast majority play just like they do on the console itself.
That includes the ability to play multiplayer on certain titles and PS Now games also reward gamers with Trophies like their disc-based counterparts.
Save games are stored in the cloud too, so you can pick up from where you left off no matter what device you played on last.
What devices is it available on?
Sadly, while PS Now was originally available on PS3, PS Vita, the PlayStation TV set-top-box and select Sony Bravia TVs, support was removed earlier this year.
However, Windows PC support has been added more recently, although it can only stream games, not download them.
Therefore, you can use PS Now on PlayStation 4 and PC. As far as we are aware, there are no plans to expand to other devices any time soon.
What internet connection do I need for PS Now?
It is recommended that you have a broadband connection of at least 5Mbps. Sony also suggests that you will get a more stable experience if you use a wired connection over a wireless one.
What games are available?
At present, almost 600 games are available on the platform, which are made up of many PS3 titles and triple-A PlayStation 4 games, including BloodBorne, God of War III Remastered, Dirt Rally and Until Dawn.
How much does PlayStation Now cost?
All games are available on a Netflix-style monthly subscription model.
First time users get a 30-day free trial period and it then costs £12.99 per month in the UK, $19.99 in the US.
When and how can I get it?
PS Now is available now in the UK, US, Canada, Austria, Belgium, France, Germany, Ireland, Japan, Luxembourg, Switzerland and The Netherlands. You can get it through the PlayStation Store on your PS4.
The Windows PC version is available here.
What are the alternatives to PS Now?
Sadly, after relaunching a couple of times, OnLive - PlayStation Now's biggest rival a couple of years ago - folded, selling its technologies to Sony to help the company improve its service sometime in the future.
The only viable alternative currently available comes from Nvidia, with its lag-free GeForce Now service (formerly known as Grid). It is available for Shield TV, Shield Tablet and Shield handheld owners and is capable of streaming games at 1080p in 60 frames per second. There are new games added all the time, but the current list already has a fair share of the biggest PC titles of the last couple of years.
Xbox is also planning to start public trials of its own cloud gaming platform Project xCloud in 2019. More details on that will be revealed closer the time.
Finally, Google's Project Stream plans to provide a cloud gaming service through its own web browser, Chrome. Testing is currently underway, with gamers able to play Ubisoft's Assassin's Creed: Odyssey running through the browser. Sadly, it is a limited test, expiring in January, and is only available in the US at present.