Social video platform Chill has added an additional $8 million in Series A financing to its war chest amid its quest to replace cable TV and YouTube as the default location for discovering and consuming video content.

The latest round was led by existing Chill investor Kleiner Perkins Caufield & Byers with additional participation from Hollywood talent agency William Morris Endeavor (WME), Atlas Ventures, and Chris Sacca’s Lowercase Capital.

Additionally, the company announced a partnership with celebrity gossip and entertainment news network TMZ. Chill is now the official social video platform of TMZ, joining its existing content partnerships with Jimmy Kimmel Live and PUMA, among others. TMZ quietly launched a channel on the Chill platform less than one month ago and has already seen more than one million video views and has amassed nearly 16,000 followers.

Chill has grown its community of registered users to more than 18 million in the five months since the January launch of its current product, with approximately 10 million monthly active users. The site allows users to view and share video content across their social graph and view content recommended by social connections. Additionally, Chill functions as a network of its own, allowing users to build new connections based on shared affinities for certain topics.

“Chill builds upon the power of social platforms to organize video into interesting, relevant streams and distribute that content to users on the wide variety of devices they love using,” Chill investor and Kleiner Perkins partner Chi-Hua Chien.

Unlike social video competitors, Socialcam, Viddy, and Klip which emphasize user generated content, Chill is focused instead on premium content. Users can simply and easily tag and share video hosted elsewhere on the Web using a simple repost bookmarklet, a la Pinterest. Also unlike its competitors, Chill is primarily a desktop Web experience, although the company has declared improving its mobile experience a focus of its future product roadmap.

As its platform continues to evolve, Chill aims to disrupt viewing habits and find new social ways to mobilize audiences towards programming. “In a world with billions of connected smartphones, tablets and TVs, the opportunity to reimagine the future of entertainment is tremendous,” says Kleiner’s Chien.

Although the company did not break down the individual investments in the latest round, sources close to WME suggest the agency contributed approximately $2 million. This would be a rather sizeable sum relative to its typical venture investments the agency is known to make. Beyond the cash, expect the WME partnership to provide Chill with increased access to premium content and entertainment properties.

Chill was co-founded by Ad.ly and Namesake co-founders and former MySpacers Brian Norgard and Daniel Gould. Chill previously raised $2 million from Kleiner, 500 Startups, Redpoint Ventures, CrunchFund, Science Media, social media maven and Lady Gaga manager Troy Carter, and Science founding partner Mike Jones.

Amid the ongoing uproar about the limited availability of HBO’s premium content catalog and given the sorry state of online video, this is a space begging to be disrupted. With its focus on premium content and social curation, as well as strong content partnerships, Chill is well positioned to have a say in where the market ends up.

“The way people consume entertainment is radically shifting,” says Norgard. “Old technologies are giving way to a more social and personalized world where people can enjoy the best content anywhere and at any time.”

[Image Source Verne Troyer]