Lindsay Lohan reveals on her MySpace page Wednesday that she has a half-sibling.

The 22-year-old actress wrote on her blog, “My father just let my family and [me] know, amongst other [things] that he had another child after my little sister Aliana. Or maybe he had it before Aliana?? Either way, he cheated on my mother and that really sucks.”

Of course, a Lindsay blog post won’t be complete without her father responding to Lilo’s claim. Michael Lohan, Lindsay’s dad, then tells People magazine that he believes there’s a “99% chance” that the message was written by Linday’s girlfriend, Samantha Ronson and denies he has another child with someone else than Lindsay’s mom.

Who do you think is lying this time? Check out the latest pictures of Lindsay Lohan after the jump…