The book is a collection of anecdotes that Nichols shared with friends and acquaintances before his death in 2014. In the book, New York Times columnist Maureen Dowd recounts what Nichols told her about the evening.
Apparently, Nichols was standing behind Monroe, completely invisible, when she sang the sultry rendition of "Happy Birthday."
He claimed that Monroe was not wearing any underwear under the notoriously tight and revealing dress she wore that night.
Monroe's performance fueled rumors that she was having affairs with both Kennedy and his brother Robert, and she died less than three months later at the age of 36 from a drug overdose.
The infamous dress sold at auction in Los Angeles for a staggering $4.8 million (£3.7 million) in 2016.
