AceShowbiz - Pop star Ke$ha's family history has come under scrutiny after a man purporting to be her father accused the singer of lying about not knowing the identity of her real dad. Engineer Bob Chamberlain, a musician himself, has been left devastated by the "TiK ToK" hitmaker's repeated assertions about her fatherless childhood - because he alleges he was in regular contact with her and her mother Pebe Sebert throughout her youth.

He claims they spent time together as she was growing up and he even has photos of the pair and letters from his famous daughter, addressed, "Dear Dad...". He lost contact with Ke$ha, now 23, four years ago, but was left baffled when he heard the singer had completely erased him from her memory.

Speaking out for the first time, Chamberlain tells America's Star magazine, "I was in her life from the time she was born until she was 19 years old. The contact ended, and I have no idea why. Maybe someone around her thought it would be better to perpetuate those myths; I don't know."