Liberace's Lover Scott Thorson Dead at 65

Scott Thorson -- who dished on his romance with Liberace in his 1988 memoir "Behind the Candelabra" just a year after the famed pianist’s death -- has died.

Thorson died on August 16 -- he'd been a patient at an L.A. healthcare facility, where he had been dealing with cancer and a heart condition.

Thorson was hired as Liberace's personal friend and companion when he was 18 and the icon was 57 -- which kicked off their 5-year romance.

Thorson got fired from his gig in '82 -- and then hit Liberace with a $113 million lawsuit ... which ended up being the first same-sex palimony suit ever filed in the U.S.

But, Liberace kept denying he was homosexual, and they ended up settling the suit out of court. Liberace died the next year, in 1987, from HIV/AIDS-related complications.

Thorson's memoir came out the next year ... and was later turned into the 2013 HBO film of the same name, directed by Steven Soderbergh, starring Matt Damon as Thorson and Michael Douglas as Liberace.

Aside from his time with Liberace, Thorson was also known as a key witness in the 1981 Wonderland Massacre trial.

Thorson was 65.