The first Universal theme park in Europe will be built in the UK, the government has promised, BBC reports.
The attraction is planned for the site of a former brickworks near Bedford and could create an estimated 28,000 jobs before opening in 2031.
Universal estimated the 476-acre complex could attract 8.5 million visitors in its first year.
Sir Keir Starmer said the multibillion-pound investment by the company would "see Bedford home to one of the biggest entertainment parks in Europe, firmly putting the county on the global stage".
The prime minister joked that his children, aged 14 and 16, were uncharacteristically interested in the news.
"They don't take that much interest in the announcements I'm making every day, I have to admit, but this one has really caught their eye," said Starmer, speaking on a visit to Kimberley College in nearby Stewartby.
Universal, which has made films including Minions and Wicked, has theme parks in Orlando and Los Angeles in the US, as well as in Japan, Singapore and China.
The site - which is the former Kempston Hardwick brickworks - will be "one of the largest and most advanced" theme parks on the continent once complete, the production company says.
A full planning proposal will be submitted to the UK government, with construction expected to start in 2026.
Universal had previously given its name to the PortAventura resort in Spain, but it is understood the UK attraction will be the first in Europe it has designed and built from scratch.
Universal Destinations and Experience said 80% of those employed in the new jobs would be from Bedford, central Bedfordshire, Luton and Milton Keynes.
Culture Secretary Lisa Nandy hailed the "landmark investment" as "fantastic news" for the economy.
"This is not just about bringing great American creations to Britain, this is also about showcasing great British creations to the world," she told BBC Breakfast.
"These are things like James Bond, Paddington Bear, these are things like Harry Potter. We've got so much to be proud of."
Universal's Orlando resort in Florida brought in 9.75 million visitors in 2023, while its Hollywood resort saw 9.66 million the same year - according to the Theme Index Report.
In 2016, NBCUniversal agreed to a seven-year deal with Warner Bros. That meant it had television rights to show the Harry Potter films and the Fantastic Beasts franchise.
The prime minister said the theme park would create jobs across construction, artificial intelligence and tourism.
Chancellor Rachel Reeves said the government had agreed with Universal that British steel would be used "where possible" on the project.
"That's the case with HS2, with Heathrow, and with this private investment here in Bedfordshire," she said.
According to plans from Universal Destinations & Experiences, the UK site would include a theme park, a 500-room hotel and a retail complex.
Universal has already bought 476 acres for the project, but could buy more land to increase the plot to about 700 acres - which would improve transport links.
Residents living in surrounding villages have responded positively to the plans, though some are concerned infrastructure will not be enough to support the amount of expected visitors.
Universal said it had surveyed more than 6,000 local people and organisations, and 92% of those supported the project.
Universal said it would make upgrades to the Wixams railway station and build a new station on the East West Rail line near the resort.