YouTube isn't going to be completely free anymore.

It's been rumoured that Google wants to offer a subscription-based version of YouTube by the end of this year, which would let you see millions of videos on YouTube without having to watch adverts, among many other things, but now it looks like everything about this version of YouTube is finally coming to fruition.

Bloomberg has claimed Google wants to launch a subscriber YouTube to increase revenue and better compete with rivals in the paid video space, such as HBO Now and Netflix. Google is even beginning to warn content creators via email that they must agree to terms that would let it include clips in its new subscription product.

"We're excited to...[offer] fans an ads-free version of YouTube for a monthly fee. By creating a new paid offering, we'll generate a new source of revenue that will supplement your fast growing advertising service," the email said. "Launching a new paid offering will require us to update your terms".

This isn't the first time Google has toyed with the idea of giving once-free, advert-based stuff a paid subscription option that guarantees no adverts. It recently introduced YouTube Music Key, for instance, which is an attempt to boost original music video content on YouTube as well as let viewers pay for said content, ad-free.

The idea is that YouTube will offer all the same videos without adverts for a monthly fee (which hasn't been set yet). It will also offer offline access to videos. The beta version of YouTube Music Key, which offers offline access as well, costs $10 a month, so the new subscriber YouTube might cost around the same.

According to The Verge, YouTube also plans to let content creators put specific videos behind a paywall, which means their subscribers will need to sign up for the premium version of YouTube in order to view them.

You can see a copy of Google's email in the gallery above.

READ: What is YouTube Music Key?