The resulting firm will be a global leader in premium content, a multi-platform and one of the most important producers and providers of entertainment and communications content worldwide, Efe news reported on Tuesday.
CBS and Viacom are reuniting under the umbrella of US communications media magnate Sumner Redstone with the aim of competing with "streaming" platforms such as Netflix, HBO and the future Disney+.
The company said that it will hold a leadership position in the US, European, Latin American and Asian markets, including commanding the largest television viewership in the US as well as the largest cable market share in all demographics.
The merger also includes Paramount Pictures studios, which has been a global producer and distributor of films for more than a century and continues to be a box office leader worldwide.
The president and CEO of Viacom, Bob Bakish, will head the new company, and Joe Ianniello, the president and acting CEO of CBS, will remain chairman and CEO of CBS.
"Our unique ability to produce premium and popular content for global audiences at scale - for our own platforms and for our partners around the world - will enable us to maximize our business for today, while positioning us to lead for years to come," said Bakish.
"I couldn't be more excited about the opportunities ahead for the combined company and all of our stakeholders - including consumers, the creative community, commercial partners, employees and, of course, our shareholders," he added.
Ianniello hailed the merger and the opportunities it will provide, saying: "At CBS, we have outstanding momentum right now - creatively and operationally - and Viacom's portfolio will help accelerate that progress."
The resulting firm will include CBS, Showtime, Nickelodeon, MTV, BET, Comedy Central and Paramount Networks, along with one of the largest libraries of intellectual property with more than 140,000 TV episodes and 3,600 films, ranging from "Star Trek" to "Mission Impossible."
It will also include 750 new series in production and ViacomCBS will become one of the biggest earners in terms of content, with the separate firms having jointly earned more than US $13 billion last year.
With more than 4.3 billion customers all around the world, CBS produces content in 45 languages and has a large presence in the United Kingdom and Australia, among many other countries, as well as a significant presence throughout the Spanish-speaking world.
Both firms are almost 80 per cent owned by National Amusements, Redstone's conglomerate, which has guaranteed that the company will have enough votes to achieve the merger.
The merger, which now depends on obtaining regulators' approval, is expected to be finalized by the end of the year.
This is not the first time that CBS and Viacom have wanted to reunite, already having tried to do so in 2016 although at that time CBS resisted because of a lack of agreement about the valuation of Viacom, which originally acquired CBS in 2000, with the firms separating several years later.
( With inputs from IANS )