Justin Timberlake is not bringing “SexyBack” tonight … ’cause he’s got a nasty case of the flu and can’t perform tonight.

The singer-songwriter posted an apology to his Instagram Thursday evening … telling fans he was heartbroken, but he needed to cancel the show in Columbus, Ohio because he couldn’t even get through soundcheck.

He says it kills him to disappoint his fans and all the members of his team who worked so hard to put the show together … and, he promises everyone will receive refunds for their tickets.

Mary Kate Cornett and her parents are coming off an emotional 48 hours … one which her parents said left them feeling helpless — though a recent development may help the Cornetts take some of their power back.

We spoke with Mary Kate Cornett’s mother, Leslie, and her father, Justin … who tell us all the claims about their daughter floating around on the internet are untrue.

We’re told the last couple days have been difficult for the trio, who are all spending time together in Oxford, Mississippi — the city where the University of Mississippi resides.

As you know, Cornett — an 18-year-old freshman at Ole Miss — has been dragged on the internet for allegedly sleeping with her boyfriend’s father … which resulted in her being treated “like she wasn’t a human being” online, according to Leslie.

Justin says he and Leslie flew from Houston to be with their daughter when this story started taking off … but, despite being with Mary Kate to keep her safe, he says “we felt absolutely helpless.”

However, the family seems to be fighting back now … ’cause TMZ has obtained a copy of the police report they filed — claiming Cornett’s been the victim of cyberstalking and harassment.

The police report lays out a narrative … in which Cornett claims she found out about the viral rumor while at a salon in the area — and, she immediately raced over to her boyfriend, Evan Solis‘ house to assure him the rumors weren’t true.

Mary Kate and Evan have both denied all these claims on their Instagram accounts … with Mary even calling out several prominent sports figures like Antonio Brown and Pat McAfee for fueling the unsubstantiated rumor.

Gene Hackman‘s wife was very serious about the star’s health, putting him on a strict diet years ago … so says his longtime friend and former business partner.

Doug Lanham, a close friend and former business partner, tells TMZ … Betsy Arakawa made sure Gene was eating right — demanding he stick to a strict diet.

In fact, Betsy took it so seriously, Doug says Gene was only able to sneak a cheat meal when they were out golfing … this despite owning a bar and bistro for years.

Hackman retired from the biz about seven years ago … selling off his stake for a tidy profit, Doug says.

Despite leaving the restaurant industry, Doug says Gene would often come by for a meal — because of the diet Betsy had him on he’d often order either the halibut or rice-paper salmon rather than a big steak.

Usually, when Gene came by he’d also pick up the tab for a few lucky customers too … and, he even made all the art for the restaurant. So sounds like his post-acting years were still very busy.

Doug remembers Gene as a jokester who would play dumb little tricks on him … like putting his finger to Doug’s back and telling him to “reach for the stars.”

Despite his love for the quiet lifestyle, Doug says Gene was always cool about sharing Hollywood stories with his friends.

As we told you … Gene and his wife Betsy were found dead in their home Wednesday — and, the warrant application shows the police feel their deaths have a suspicious element to them.

A caretaker of the neighborhood made the 911 call to police … who arrived and pronounced the two dead at the scene. The investigation is ongoing.x

Gene was 95 … Arakawa was 63.