(LOS ANGELES) -- If she doesn't know it already, Lindsay Lohan will find out later on Thursday that she has a half-sister she never knew about.
TMZ.com reports that during a taping of the syndicated program The Trisha Goddard Show, Michael Lohan learns that he is the father of a 17-year-old girl when the results of a DNA test are revealed. The girl, named Ashley, and her mother, Kristi Horn, also appear on the show.
As seen in a clip posted on TMZ's website, Ashley is clearly shaken by the news, and when Michael tries to give her a hug, she initially objects.
Michael has four children with ex-wife Dina Lohan, including Lindsay. Michael and Dina were married from 1985 to 2007.
The episode of The Trisha Goddard Show with Michael Lohan airs on Thursday.
Copyright 2012 ABC News Radio