Warner Bros Discovery shareholders have approved the company's $111bn (£82bn) takeover by Paramount in a deal which could drastically alter the media landscape.
The deal would see Paramount Skydance take control of all of Warner Bros' titles and channels, which include Harry Potter, Game of Thrones and news network CNN.
"With Paramount, we look forward to creating an exceptional combined company that will expand consumer choice and benefit the global creative talent community," Warner Bros chair Samuel DiPiazza said.
The deal still needs approval from the US Department of Justice and European competition regulators.
The shareholders' backing of the deal follows a dramatic months-long saga, following an earlier takeover bid for Warner Bros by Netflix, which the streaming service later withdrew after Paramount submitted a rival, higher offer.
Paramount, which is looking to transform itself into a Hollywood heavyweight, is backed by tech billionaire Larry Ellison and led by his son David.
Ellison, chief executive and chairman of Paramount and a major Republican donor, is hosting a dinner with Trump on Thursday at the U.S. Institute of Peace in Washington DC.
Hulk actor Mark Ruffalo is expected to join protesters outside the building to demonstrate against what organisers have described as a "corruption gala", given the regulatory hurdles still facing the companies. The protesters have also raised concerns about how the Ellisons' ownership of CNN will impact the news network.
Trump has frequently attacked CNN over its reporting of his policies. He said in December that he believed the news network should be sold as part of any Warner Bros takeover.
He called CNN's bosses "corrupt or incompetent" and said they should not be entrusted to run the network.
As well as concerns over CNN's future, a slew of actors, directors and filmmakers have opposed the takeover on the grounds it could further harm an already struggling industry.
In April, more than 1,400, including Emma Thompson, Ben Stiller and Javier Bardem, signed a letter warning of its impact.
"The result will be fewer opportunities for creators, fewer jobs across the production ecosystem, higher costs, and less choice for audiences in the United States and around the world," the letter said.
Paramount responded by pledging its commitment to talent and "ensuring creators have more avenues for their work, not fewer".
Democrat Senator Elizabeth Warren said the deal would be "an anti-trust disaster" and state attorneys general would try to stop it.
"The Paramount-Warner Bros merger isn't a done deal… we need to keep up this fight," she said after the announcement.
But Mike Proulx, of market research firm Forrester, said Washington "is likely to rubber stamp the deal".
"The real regulatory pressure sits overseas, where European authorities will focus on structural market impact. A process that is likely to shape the timing and terms of this deal," he added.
The Warner Bros shareholders on Thursday voted to approve the deal with Paramount, which DiPiazza said will "unlock the full value of our world-class entertainment portfolio".
If the deal is approved by regulators, Paramount will fold Warner Bros' HBO Max streaming customers into its portfolio. It would also take ownership of the Food Network, the Discovery Channel and a range of sports offerings.
Paramount's traditional networks already include brands such as Nickelodeon, CBS and Comedy Central.
The company said it expects the takeover to be finalised by September, pending regulatory clearances.
