Jul 19, 2011 09:15 GMT  ·  By

Zynga, the biggest social gaming company around with a massive audience on Facebook, is preparing to go public and has been making all of the necessary paper work.

It has now made an addendum to its S1 filing with the US Securities and Exchange Commission, in which it reveals all of its minority investors and the extensive and complicated deal it has with Facebook.

The fact that Google had invested in Zynga has been rumored for more than a year now. Google even made some vague comments about it and it has been a pretty open secret.

But neither company has confirmed the investment until today when Zynga revealed its existing minor investors, with Google at the top of the list.

Also on the list is Japan's Softbank, and a couple of companies related to the Russian fund DST, Digital Sky Technologies Limited and DST Global Limited. How much each company owns was not revealed.

Google's involvement has always been linked to a game platform the company has been rumored to be working on. Now that Google+ is live, it's a given that Google+ Games will become available and there are clear indications that it is coming.

Having Zynga, which has a number of successful titles with hundreds of millions of players in total, on board is great for Google. There's just one problem, Zynga can't take any of its most popular games and launch it on Google+.

Well, technically, they could, but the games would require users to provide their Facebook credentials to log in. This is because Zynga and Facebook have a very tight exclusivity deal, signed last year.

Still, having Zynga as a launch partner for Google+, with possibly exclusive games could be a bonus for the new social network. However, the games section may still be a while off, for now Google+ provides just the basic functionality you'd expect from a social network, there is no platform or API yet. [via All Things D]