Viacom said Tuesday it's agreed to buy free TV streaming service Pluto TV for $340 million in cash.

Founded in 2013, the ad-supported, internet-based service streams more than 100 channels of on-demand content, including movies, sports, news and lifestyle programming. The Los Angeles-based Pluto TV has 12 million monthly active users who stream content across devices such as Roku, Amazon Fire TV, Android TV, Apple TV, Chromecast, and Sony PlayStation consoles, as well as Samsung and Vizio TVs.

"We see significant white space in the ad-supported streaming market and are excited to work with the talented Pluto TV team, and a broad range of Viacom partners, to accelerate its growth in the US and all over the world," Viacom CO Bob Bakish said in a statement.

Viacom, the parent of networks like MTV and Nickelodeon, was once the disruptive TV upstart that locked in on young audiences and helped shape youth culture. But as young viewers have abandoned regular TV in favor of watching YouTube and streaming services like Netflix, Viacom has been grappling with how to reckon its networks with a young audience that is watching video elsewhere.

PlutoTV, a free streaming service that feels a lot like regular linear TV with ads, is a meaningful hint of how Viacom wants the future of MTV, Nickelodeon and Comedy Central to look -- a bridge between old-school cable and new-school internet television.

The acquisition announcement makes Viacom the latest gigantic company jumping on the streaming-video bandwagon. Just this year, streaming services are expected from Apple, which has been reportedly investing $1 billion in programming for its as-yet-unconfirmed service; Disney, which will be the exclusive place to stream all its blockbuster Marvel, Pixar and Star Wars films; and WarnerMedia, the AT&T unit that owns HBO and movies like Harry Potter and Wonder Woman.

Viacom's acquisition is expected to close in the first quarter of 2019.

(Disclosure: CBS, the parent company of CNET, was spun off from Viacom in 2005. Both companies remain majority owned by National Amusements.)

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