Mackenzie Phillips, left, and Bijou Phillips, right. (WENN.COM file photos)

Actress Bijou Phillips has blamed her half-sister Mackenzie for ruining her relationship with their father John.

Mackenzie shocked fans by detailing her 10-year sexual affair with The Mamas & The Papas singer in a new memoir, High on Arrival - and she hit headlines last week when she sat down with Oprah Winfrey to talk about the scandal on TV.

But Bijou, John's youngest child, has admitted Mackenzie told her about the alleged romance years ago - and it had a devastating effect on her teenage years, stripping her of her innocence and leaving her wary of her father.

The 29-year-old insists it took her years to repair her relationship with the California Dreamin' hitmaker after hearing about the rape allegations.

In a series of messages posted on her Twitter.com page, Bijou writes, "Exploiting the history of our family and the death of our father John Phillips for the release of a book is disgusting. Allegations of sexual abuse are not only hurtful, but malicious when he is not here to defend himself.

"When I was young my sister told me about this - it ruined my life and my relationship with my father. Up till that point, I was a normal kid. I got good grades, loved my horse, was pretty innocent. I moved out to NYC at 13. Started doing drugs, did not talk to my Dad anymore... I was deeply f***ed up. I'm 29 now, I've talked to everyone who was around during that time, I've asked the hard questions. I do not believe my sister. Our father is many things, this is not one of them. My dad and I made up when I was 20, a year before he died. I'm sad I lost those years with him, and I lost those years at home."

John Phillips died of heart failure in 2001, aged 65.