Lindsay Lohan has discovered she has a long lost half-sister.
Michael had previously denied that he was the father of 17-year-old Ashley Horn, but appeared on The Trisha Goddard Show in the US to take a paternity test. It proved he was indeed the girl's dad, making her Li-Lo's half-sister.
Li-Lo, who has had an up and down relationship with her dad, has not commented on the news.
Michael was married to Lindsay's mum Dina from 1985 until 2005 and they had four children together - Lindsay, 26, Michael, 25, Ali, 18, and 16-year-old Dakota.
He is currently expecting his sixth child with girlfriend Kate Major.