FTX bad boy Sam Bankman-Fried’s cushy house arrest was brightened up Tuesday by a visit from a sexy single crypto influencer who said he seemed “surprisingly optimistic” ahead of his trial on multiple fraud charges, The Post has learned.

Sources said Tiffany Fong stayed late into the night during her trip to see the accused fraudster — holed up at his mom and dad’s house in Stanford, Calif. — who has been federally charged in what is shaping up to be one of the biggest financial scandals in history.

Fong, 26, who specializes in crypto content, was the first person FTX founder Bankman-Fried opened up to about his rumored polyamorous sex life in a phone call that was first published in November.

However, when contacted by The Post, she said she had met the ankle-monitored former billionaire in the home’s library and their chat was strictly business.

Fong said Bankman-Fried “seemed similar to how he always is,” adding that he “remains surprisingly optimistic, although aware of [the gravity of his situation],” referring to the prison sentence of up to 115 years he faces if convicted on all charges.

“He doesn’t seem to want to talk too much about worst-case scenarios,” she added.

Bankman-Fried was arrested in the Bahamas, where he had been running the FTX crypto exchange before its collapse, on Dec. 12. He was the jailed for a week in the country’s notorious, rat-infested Fox Hill prison before agreeing to be extradited to the US.

Fong added they had “touched upon his time in Fox Hill,” but would not be drawn out on how he’d fared in the jail.

She added: “He definitely expressed regret and remorse a number of times” during their chat for the customers who lost millions as the result of Bankman-Fried’s alleged financial misdeeds that led to FTX’s collapse.

“He’s trying to gather his take on events. … He sounded like he was trying to gather his thoughts about what happened,” Fong added, noting Bankman-Fried was on his computer as they talked, but was not gaming.

As part of the terms of his $250 million bail agreement, Bankman-Fried is allowed on the internet but not allowed to make purchases over $1,000 or start a business. He is only allowed to leave the home for exercise, legal meetings or court-mandated substance abuse and mental health treatment.

According to sources: “Bankman-Fried’s parents have to formally approve any visitors beforehand, so they know what’s going on. It’s their house.”

Fong — who boasts 19,000 YouTube followers and 39,000 Twitter followers — describes her current occupation on LinkedIn as a self-employed “Reluctant Crypto Content Creator” and said she just happened to be in nearby San Francisco to spend the holidays with her sister and her husband when she got a message from Bankman-Fried.

Quickly rising in the crypto community, Fong caught the notice of the Biden administration, which invited her to the White House Christmas party, where she quipped that she let President Biden “smell my hair” in an Instagram post of her smiling beside the president.

In another post from inside the White House, she joked: “hello @potus, i have some questions about your son’s laptop.”

She has closely followed FTX’s implosion and Bankman-Fried’s legal troubles on her YouTube channel, which she claims she started to “vent” about cryptocurrency.

In her first video, posted in June, Fong explained how she lost $200,000 in the collapse of the US crypto lender Celsius Network, which filed for bankruptcy in New York in July.

Fong also closely covered the fallout from Celsius Network and its embattled founder and former CEO Alex Machinsky on her channel.

Bankman-Fried’s interview schedule hasn’t slowed down despite him being under house arrest at his Stanford law professor parents’ $4 million house — which they had to put up as collateral to meet his bail requirements.

On Friday, he was visited for several hours by bestselling author Michael Lewis, as he appears to be turning the collapse of his crypto empire into a blockbuster.

Sources told The Post on Tuesday that the “Moneyball” and “The Big Short” writer met with Bankman-Fried just hours after he landed in California — presumably to talk about how a 30-year-old went from a billionaire CEO to facing up to life in prison in a matter of weeks.