Premium TV works with companies including the Premier League, Chelsea Football Club, Virgin Media and Warner Music.
Blavatnik is the chairman and president of Access Industries, a privately held, US-based industrial group. Access Industries owns a diverse range of investments, with its media interests including TopUpTV.
The company started off hosting websites for football clubs, but has branched out to become a major digital rights business, streaming live events over the internet. It hosts over 150 websites and more than 50 mobile internet sites.
It is owned by private investor Quest Turnaround, which acquired it from NTL when it filed for bankruptcy in the US in 2002. The company was £30m in debt when Quest took control, but now makes a profit and has growth of over 65% a year.
The deal to buy Premium TV ties in with its strategy of offering platforms for online media delivery, and for exploiting digital rights. It will also help Premium TV to expand globally.
Oliver Slipper, CEO of Premium TV, said: "In Access, we have a parent company who understands our vision and can help us become the world's leading digital service provider to the sports and entertainment sectors."