EXCLUSIVE: Gay Rumors, Secret Love Child Allegations and a 'Publicity Stunt' Marriage – Radar Lifts the Lid on Hollywood Heartthrob Rock Hudson's Untold Story

It was his big secret: He was gay. While Rock Hudson was out to his closest friends – and every actor and crew member on every movie set seemed to be in the know that he was gay, as well – he died on Oct. 2, 1985, from AIDS at age 59, never publicly acknowledging his true sexuality.

Now, 40 years later, RadarOnline.com has learned that being gay wasn't the only secret the matinee idol – who famously romanced Elizabeth Taylor and a host of other Hollywood actresses onscreen – was determined to take to his grave.

"There were many secrets," one insider said of the late heartthrob, who made millions of moviegoers –women and men alike – swoon.

"While he didn't have many long-term romances, he had affairs with other actors. Also, there were rumors of a love child. And what did his wife really know?"

In the bombshell HBO documentary Rock Hudson: All That Heaven Allowed, Hudson himself is quoted as saying: "I like to keep my secrets to myself ... I guess they'll die with me."

Author Mark Griffin, who wrote All That Heaven Allows, the biography that inspired the film, acknowledges in the documentary the secrecy with which Hudson's private life was shrouded. While Rock's sexuality was known by many in Hollywood circles, he was hell-bent on protecting the identity of at least one lover, someone who, according to the insider, was a famous actor himself.

"Rock confided in a few close friends, but he refused to name the man publicly, fearing the backlash the other actor might face," said the insider. "Rock would never betray him."

Nothing was ever talked about as far as his private life, his Pillow Talk co-star Doris Day once said. Even more shocking are the long-whispered claims Hudson fathered a child as a young man, years before he achieved fame.

According to one report, Hudson – who was known as Roy Fitzgerald before he changed his name – was 19 when he was "seduced" by a girlfriend's mother.

Years later, the woman allegedly sent Hudson a letter revealing that their night of passion left her pregnant with a son. "There was always talk about a child," the source said.

"But Rock never addressed it, and no one ever came forward. Still, it was something people in the inner circle occasionally mentioned."

In 1955, Hudson married Phyllis Gates, his agent's secretary.

The union has long been described as a publicity stunt orchestrated by Hudson's handlers to quiet the rumors.

The couple divorced three years later. Gates claimed she had no idea during their marriage that Hudson was gay and felt "betrayed" when she learned the truth, though friends of Hudson's doubt she was unaware.

The HBO documentary also explores a rumored rivalry between Hudson and James Dean, with speculation about the true nature of their relationship. Dean, rumored to have had sex with men, allegedly criticized Hudson for maintaining a heterosexual facade in public while privately showing interest in him.

Hudson's AIDS diagnosis, made public shortly before his death, sparked a national conversation that helped reduce the stigma surrounding the disease.

"He was so brave to tell the world he had AIDS," said a source. "But there was so much more to tell – and he took those secrets to his grave."