R. Kelly’s longtime live-in girlfriend and now alleged fiancée, Joycelyn Savage is preparing to release a tell-all book about her relationship with the pedophilic R&B singer.

In an email to The Post, Savage, 26, confirmed the book will be called “Love and Joy of Robert” and “should be published on Saturday.”

“All I can say is that it is about Robert, the beginning of my life in Robert’s shadow, where things began to take off, and where they are currently going,” she wrote about the book’s contents.

Savage would neither confirm nor deny to The Post that she and Kelly, whose full name is Robert Sylvester Kelly, are engaged. “Everything will be answered in my book,” she said.

She also did not reveal whether the book would be self-published or through an established publishing house, or where the tome would be available.

This is coming after The Post obtained a letter Savage wrote a federal judge, referring to herself as Kelly’s fiancée and asking that he received a more lenient sentence for his decades-long sexual abuse of women and underage girls and boys.

Kelly was sentenced to 30 years in the sex trafficking case.