Comcast's latest channel is one that's never been on cable before: Tubi TV, one of the most popular free movie-streaming services. 

Comcast will incorporate Tubi into X1, the cable company's pay-TV service, starting Thursday, the two companies said. The new partnership means Tubi's library of movies and other programming are set to be available and searchable on Comcast X1 like a regular channel or show.  Roll out begins Thursday, and Tubi will be available to all Comcast X1 users in coming days.

Tubi has 8,500 titles, mostly movies, that anyone can watch free with advertising breaks. As Netflix has transitioned away from licensing a deep catalog of movies in favor of its own originals, Tubi has stepped into that vacuum -- but with an ad-based service rather than one requiring a subscription. 

"You can't get most of these titles on your regular on-demand services," Tubi CEO Farhad Massoudi said in an interview. The Comcast partnership will put the its catalog "in front of millions of eyeballs that otherwise wouldn't have access to these films."

The move comes after Comcast, the biggest cable provider in the US, opened its arms to Netflix,YouTube and Amazon Prime Video in the last two years, a coup after years of tension between traditional pay-TV companies and digitally delivered upstarts. Netflix and YouTube, as the two biggest online video companies of their kind, have long been poster children for cord-cutting, the trend of people forsaking pay-TV like Comcast for digital alternatives instead.

But those integrations are all with services run by the biggest tech companies in the world. Comcast adding Tubi widens the playing field to a smaller, popular start-up. Tubi doesn't share its active user figures, but it is routinely one of the top-ranked apps for its category on streaming platforms like Roku and Amazon Fire TV. 

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