US President Donald Trump has said the FBI is investigating the affair between the chief executive of Nvidia and an alleged Chinese spy.
Trump said he spoke to Jensen Huang on Monday following reports that the US believed he had been targeted in a Chinese espionage campaign.
"I asked him that question, 'Did you have any idea she was a spy?' He said 'I had no idea she was a spy' and I really believe him," Trump told reporters.
Beijing has rejected claims that Huang was targeted, with its foreign ministry saying the allegations were "entirely groundless, speculative and intended to smear and malign China".
Nvidia, which has commissioned an independent investigation into the affair involving Alice Huang, alleged to be a Chinese spy, said it had no reason to believe the company's secrets or national security were compromised.
Nvidia is the world's second most valuable company after Apple, and designs computer chips that have become central to AI technology. The revelations knocked about $250bn (£190bn) off its value on Monday as the company's share price fell by more than 4%.
Trump later told reporters at the White House that the FBI was looking into the issue, but did not elaborate on the investigation, or when it was launched. The FBI declined to comment when contacted by the BBC.
US intelligence officials believe Alice Huang, also known as Huang Le, was a spy for Beijing, according to a New York Times report. She is not related to Jensen Huang.
According to the newspaper, Secretary of State Marco Rubio sent a memo to top officials in Washington last spring, warning that the Nvidia boss was in a close relationship with a Chinese spy.
Alice Huang was managing director of Singaporean company Megaspeed, which has had dealings with Nvidia.
Trump's remarks are the first indication of whether Nvidia's Huang knew about the woman's alleged ties to Chinese espionage.
Megaspeed's office in Singapore's central business district appeared to be operational and staffed on Tuesday.
The BBC was refused entry to its floor, but spoke to a staff member by phone who said they had no comment and directed all queries to the company's PR team.
The BBC has emailed Megaspeed several times for comment.
Nvidia, co-founded by Jensen Huang, is also a major focus in the AI technology race between the US and China, with officials in Washington treating its exports to Beijing as a matter of national security - a key reason why Huang's affair has sparked concerns.
Also on Monday, Huang and Nvidia were sued in a proposed class action lawsuit in California that accuses them of defrauding shareholders by concealing his ties with the suspected Chinese spy.
The lawsuit alleges that the company lied to the media about Jensen Huang's relationship with Alice Huang, "who is suspected of seeking to help smuggle Nvidia products to China."
The BBC has contacted Nvidia for comment on the lawsuit.
At the White House, Trump was asked several times, including by the BBC, when he was made aware of the relationship. He said he was informed "over a period of time" but was not specific.
Trump said he thought that Huang was an "honourable guy and I feel very confident that he will be in good shape" after the investigations.
"I hope there's no problem, I believe he is suffering greatly," the president added.
He said he spoke to Huang on the phone on Monday "just to see if he's feeling alright, how you doing, and I asked him about that and he said he absolutely had no idea that the person in question was a spy".
Trump has raised concerns that allowing China to lead in AI would supercharge Beijing's military and surveillance capabilities.
The president added he was "sure" Chinese leader Xi Jinping would "ask me about it" when they next met.
Some workers the BBC spoke to at Nvidia's Santa Clara headquarters on Monday said it was business as usual, despite the intense attention on the company.
Nvidia has been around for decades, with Huang founding it with two other engineers in 1993, but its rise to one of the world's most valuable and powerful companies has only been recent.
It originally designed computer chips for gaming, but its decision to shift focus to AI development turned it into the powerhouse it is today.
Its chips have become so valuable to the AI buildout that the White House previously imposed controls on where its advanced products could be sold.
The H200, Nvidia's second most advanced semiconductor, had previously been restricted over concerns that it would give China's technology industry an edge over the US.
But Huang has long been against restricting sales to China, arguing that it would be better for the global rollout of AI to be powered by US technology.
In January, the Trump administration said it would allow the company to sell its H200 chips to Chinese customers under certain conditions.
Nvidia's most advanced AI semiconductors including the GB200 Blackwell super chip remain blocked from the Chinese market.
