AceShowbiz - Frank Sinatra attempted to cover up the fact he was well hung - because he thought the size of his manhood was one of many negatives about his body, according to the late star's new biographer James Kaplan. The journalist spent five years researching his acclaimed new tome, "Frank - The Voice", and reveals Sinatra wasn't like most men, who reveled in the fact he had a big penis.

Recalling a quote from Sinatra's lover Ava Gardner, in which she stated the singer was "only 110 pounds, but 10 pounds of it is c**k!", Kaplan insists Sinatra wasn't proud of his manhood. The writer tells WENN, "I think we can take it as fact that Frank Sinatra was very well-endowed."

"George Jacobs, Sinatra's valet in latter years wrote a wonderful book, called 'Mr. S', and he speaks in the book about the size of Sinatra's manhood and actually having special underwear made to kind of keep it all in. But oddly enough, it was one of the things Sinatra was self-conscious about."

"He was scarred at birth, he weighed 13 pounds at birth, he was ripped from his mother with forceps, which damaged his ear and the side of his face. A mastoid operation when he was a kid further damaged the ear; when he was an adolescent, cystic acne pitted his cheeks; he lost his hair in his early 30s, and his gluteus maximus was minimal - he had no ass at all. He sort of hated the way that he looked for a lot of his life... and I think that, while he often boasted almost about his manhood, it was one more thing that made him different."

But Kaplan's research didn't reveal how good a lover Sinatra was in the bedroom. He adds, "Ava Gardner famously reported to her ex-husband Artie Shaw, at a time when she was growing dissatisfied with Sinatra, that being in bed with him was like being in bed with a woman."

"That was reported by Artie Shaw, who was very competitive with Sinatra... but if indeed Ava ever said anything like that, I think she may have been reflecting more on Sinatra's sensitivity, his vulnerability. There were a lot of women, so he must have been doing something right... I think women were thrilled just to be with him and I think that goes a long way in the sexual experience."