Elon Musk has denied reports that he worked illegally while on a student visa in the United States after a bombshell story in The Washington Post claimed the South African-born tech mogul once admitted he “had no legal right to stay in the country.”

“I was in fact allowed to work in the US,” Musk claimed in a late night Saturday tweet.

Musk was responding to a speech of President Joe Biden riffing on the Post’s reporting that the Tesla CEO ditched his studies at Stanford in 1995 to work illegally on his first company, Global Link Information Network, which became Zip2.

“He was supposed to be in school when he came on a student visa,” Biden said at an event Saturday. “He wasn’t in school. He was violating the law.”

Musk went on to claim in tweets that he had “a J-1 visa that transitioned to an H1-B.” A J-1 is a non-immigrant academic or exchange visa that allows people to study or work in some capacities in the U.S., while an H1-B is for temporary employment. (Most J-1 visa holders are expected to return to their home country—for two years—after their program of study or training is complete.)

He didn’t specify when his visa status changed, however. Six of his former business associates and shareholders told the Post he told them he was on a student visa when his immigration status was raised as a concern internally at Zip2 and among investors.

One of the company’s board members said Musk’s immigration status “was not what it should be” for him “to be legally employed running a company in the U.S.” according to documents obtained by the Post. An investor worried he could be “deported.”

“He’s talking about all these illegals coming our way?” asked Biden Saturday, noting the irony that Musk is now supporting the fiercely nativist Republican nominee for president, Donald Trump.

Musk has indeed gone full-MAGA, dumping tens of millions of his own money into a Super PAC to help elect Trump, who has attacked migrants as “savages” and “animals” and pledged to deport millions. He’s also slated to appear at Trump’s Madison Square Garden Rally in New York City on Sunday.

Musk, who became a U.S. citizen in 2002, has even adopted Trump’s xenophobic rhetoric himself, baselessly claiming that migrant “illegals” are part of an “illegal voter importation program.”