Republican presidential nominee, former U.S. President Donald Trump, attends an Oct. 7th remembrance event at the Trump National Doral Golf Club on October 07, 2024 in Doral, Florida. [AFP]

Elon Musk is ramping up his public support of Donald Trump, telling Tucker Carlson in a conversation streamed Monday that he is "all in" on the Republican presidential candidate.

After appearing alongside Trump at a weekend rally, the world's richest man used a cozy two-hour chat with Carlson to push right-wing talking points, including what he said was the threat to democracy if Democrat Kamala Harris prevails in November's election.

"My view is that if Trump doesn't win this election, it's the last election we're going to have," the Tesla and SpaceX boss told former Fox News host Carlson.

Musk, who has increasingly courted controversy in recent years, said he believed "illegals" -- migrants -- were being deliberately transported to a handful of key states, where if they are eventually granted citizenship, they would become Democrat voters.

"Now these swing-state margins are sometimes ten- twenty-thousand votes. So what happens if you put hundreds of thousands of people into each swing state?

"So my prediction is, if there's another four years of a Dem administration, they will legalize so many illegals that... the next election there won't be any swing states, and this will be a single-party country."

The assertions from Musk -- who is himself from South Africa -- are a common refrain on the political right, which alleges a conspiracy between Democrats and immigrants.

Musk is increasingly becoming a surrogate for Trump on the campaign trail and is reportedly planning to make a number of stops in battleground states in the coming weeks.

Over the weekend, he unveiled a program promising to pay $47 to anyone who registers voters in Pennsylvania, Georgia, North Carolina, Arizona, Michigan, Wisconsin and Michigan.

The scheme is looking to copy successful referral programs the South African-born entrepreneur has used in the past with his Tesla electric cars.

In his nearly two-hour chat with Carlson, in which the two men chuckled repeatedly at each other's pronouncements, Musk said he had thrown his full backing behind fellow billionaire Trump.

"If he loses, it's going to be hard for you to pretend you never supported him," said Carlson.

"I'm like, all in, baby," replied Musk.

"How long do you think my prison sentence is gonna be?" he chortled, laughing at the idea that the tables would turn against him under a Democratic administration. "Will I see my children? I don't know."