Before the hyperloop can become a reality, the startups looking to build it will need government approval and a whole lot of cash.

One company might have just secured one of those things. Hyperloop One, the Los Angeles-based startup that has already built a working full-size prototype, announced today that it's joining forces with one of the world's most well-known entrepreneurs: Richard Branson. According to a press release from Hyperloop One, Branson's Virgin Group is investing in the company, which will rebrand itself as Virgin Hyperloop One. The entrepreneur is also joining the startup's board of directors.

Back in June, Branson hinted in an interview with British GQ that he was getting involved with the hyperloop in some way. At the time, Inc. suggested that a mogul like Branson could be the key piece the hyperloop needed to become a reality. The company had $245 million in funding before Branson's investment. But estimates for the cost to build a 360-mile rail, which is in the middle of the range the company is targeting, have come in around $24 billion.

A billionaire backer could help with that. Hyperloop One already has agreements with governments in more than a dozen locales who want to see the high speed rail built on their turf. In the U.S., it has narrowed down its potential routes to Colorado, Texas, Florida, and Pittsburgh/Chicago, though the state of Missouri has recently made a push as well.

Hyperloop One is yet to prove its technology at full scale, however. Last year, the company demonstrated a smaller version of its pod in the Nevada desert, reaching speeds of about 400 mph. This summer, it showed off a full-size version, which reached a maximum of 192 mph. The actual finished hyperloop is expected to travel at speeds of around 700 mph.

The hyperloop, first proposed by Elon Musk, uses magnetic levitation to travel along a nearly frictionless vacuum-sealed tube.

The new partnership puts Branson in direct competition with Musk. Musk, who outlined the technology in a white paper in 2013 and vowed that he wouldn't seek to build it himself, has since backtracked. One of Musk's side projects, The Boring Company, is exploring more efficient ways of digging tunnels beneath Los Angeles, and the entrepreneur recently said he's now looking to build the hyperloop himself.

Branson and Musk are already in the midst of a space showdown. While SpaceX's goal is to get to Mars and Virgin Galactic is focused more on space tourism, both entrepreneurs are interested in commercializing the skies above. Branson has additionally proposed a 'rocket plane' that can transport people from one side of the earth to the other in under 30 minutes. Musk last month suggested that his yet-to-be-built 'Big F--king Rocket,' to be used primarily for getting to Mars, could serve the same purpose.

Hyperloop One and Virgin didn't reveal the size of the investment. In the release, Branson revealed he had met with Hyperloop One's leadership team this past summer and seen its test track in Nevada in person.