She's the product of a fling with his friend's wife

Referred to only as 'B', the woman has come forward via handwritten letters inside a new Mercury biography written by Lesley-Ann Jones.

"Freddie Mercury was and is my father," one reads.

"We had a very close and loving relationship from the moment I was born and throughout the final 15 years of his life. He adored me and was devoted to me.

"The circumstances of my birth may seem, by most people's standards, unusual and even outrageous. That should come as no surprise. It never detracted from his commitment to love and look after me. He cherished me like a treasured possession."

According to The Daily Mail, the Queen frontman gifted 'B' 17 volumes of his personal journals before passing away from pneumonia in 1991.

Medical professional 'B' lives in Europe and has children of her own, while her mother's identity is described as one of Mercury's close friend's wives that he had a fling with.

In other music-related news, Billy Joel has been forced to cancel his upcoming tour following a brain disorder diagnosis.

Known as Normal Pressure Hydrocephalus (NPH), it's caused by build-up of fluid on the brain and can cause problems with vision, hearing and balance.

"Under his doctor’s instructions, Billy is undergoing specific physical therapy and has been advised to refrain from performing during this recovery period," a statement from his people read.

"Billy is thankful for the excellent care he is receiving and is fully committed to prioritising his health. He is grateful for the support from fans during this time and looks forward to the day when he can once again take the stage."

The 'Piano Man' singer was scheduled to play at venues including Anfield in Liverpool, and Edinburgh's Murrayfield Stadium.