Hollywood is “gripped with fear” after a womanizing Tinseltown A-Lister has been diagnosed positive for HIV — panicking his long list of sexual partners, according to a published report.

“It has now become common knowledge that this star is HIV positive, something he has known for years,” an insider told The Sun newspaper of London, which attributed its report to unnamed sources, and didn’t name the infected Lothario.

“His lawyers are bracing for the threat of potential action.”

The source continued: “The reality is that if he’s knowingly put women at risk, then that’s disgusting and it’s only a matter of time before that becomes public.”

Friends have urged the actor to come forward, but he has so far refused, according to The Sun.

“He’s distraught about the possibility of the illness becoming a defining quality of his career,” a source told the site.

The actor’s list of exes includes “an award-winning actress, a religious movie star, a top Hollywood personality with a controversial past, a TV star, a media personality and a glamour model,” the site reported, without naming names.