Withered and shrunken to a skeletal 90 pounds, frail Playboy boss Hugh Hefner is facing his tragic final days, friends fear.

In fact, it is said that the 90-year-old is so desperate to keep his plummeting health a secret, he’s hidden from the public eye since May and insists that guests sign a legal document banning them from discussing his condition.

“Hef’s a shell of his former self,” said a source. “His body has given out and he can’t even walk anymore. He has to be lifted in and out of a wheelchair. Most of his buddies are convinced he won’t live much longer.”

Meanwhile, the vain, smoking-jacket-clad recluse insists he’s the picture of vitality.

“I wish the media had informed me a little earlier in the week that I’m sick,” he said. “I might have cancelled my weekend plans.”

Playmate Carla Howe ripped the lid off of the shocking, urine-reeking squalor inside Hefner’s once-glitzy 12-bedroom Playboy Mansion.

In bombshell revelations, she disclosed that “the mattresses on our beds were disgusting — old, worn and stained. The sheets were past their best, too.”

Howe revealed the orgies and star-studded parties have been replaced with early bird dinners, quiet nights playing chess and a squad of nurses tagging after Hef in the vast home.

His tragic, downward decline increased after his kid brother, Keith, died in April at the age of 87, one day before Hef’s 90th birthday.

“It ripped him apart,” noted a pal.

Two months later in June, the Playboy Mansion, once the gold standard of sexual excess, sold for $100 million to investment guru DarenMetropoulos — half its $200 million asking price.

Generous Daren told Hef he could live out his life at the mansion — and the pin-up king accepted the offer.

But he now rarely leaves his bedroom. He was even a no-show at his annual Midsummer Night’s Dream bash hosted by his son Cooper.

Two weeks ago, cops rushed to the Playboy Mansion amid false rumors Hef had died. He’s alive, but “we’ve heard he’s sick,” said Spencer T. Kuvin, the Florida attorney representing Chlboe Goins, who claims she was molested at the mansion by Hefner’s guest Bill Cosby in 2008.