An A-Lister has been accused of being diagnosed with HIV for years and keeping it a secret, panicking his long list of sexual partners.

"It has now become common knowledge that this star is HIV positive, something he has known for years," an insider tells The Sun.

Reports say the superstar has a long list of high-profile sexual partners, and his lawyers are aware of the situation.

"His lawyers are bracing for the threat of potential action," the insider said. "The reality is that if he's knowingly putting women at risk then that's disgusting and it's only a matter of time before that becomes public."

The star's name has not been released and it is not clear if he is knowingly passing the disease to other people or not.

Another source says that close friends are encouraging the actor to open up about his condition.

"Lots of people close to him have suggested he face this situation head-on and own it publicly," the source said. "Obviously it would be a huge story, but the reality is HIV is entirely treatable in this day and age and shouldn't impact his ability to work or lead a normal life."

The source added, if the actor actually does go public with his condition, "It could be a game-changer in the understanding of HIV given that he's a straight man."

The star is reportedly afraid to open up in fear of the news destroying his career and also thinks a list of sexual partners from the past may try to sue him if they find out.

HIV is treatable today, although the virus still has a certain stigma to it. People can live normal long lives with the disease as long as it's treated.

It is also a crime to knowingly infect another person with HIV, according to the Washington Post. Back in May, a man was sentenced to six months in prison for knowingly spreading the virus to both men and women.

Last year, a student from Kenya claimed to have infected 324 men. Let's hope the Hollywood A-Lister is not doing the same thing.