From the CBS site:
Among the 13 players living in the "house" in a L.A. film lot is Diane Henry, 22, of Elsmere, Ky. In the debut she flew mostly under the radar, coming off initially as a sweet, normal gal. She is joined by a cast of mostly 20-something, buff-looking players ranging from a gorgeous yoga instructor to a Paris Hilton look-a-like who called herself as "Holly from Hollywood."
The show's introduction played up Diane's job as a cocktail waitress at Argosy Casino, briefly showing her on the boat saying, "I'm Diane and the odds are in my favor." She is also a full time student at Northern Kentucky University.
Diane was also seen saying, "I hate rude people" and briefly flashed a catty side (showing she is ready to play this game) when she commented to other players that one girl, Jennifer Dedmon, "is an easy target and none of us will feel bad about her leaving."
Diane does apparently not know that the heavily tattooed, pink haired Jennifer is a serious part of the game in what producers call Project DNA. It was revealed to viewers that Jennifer, from San Antonio, and another player, Michael Ellis, from Durant, Okla., were unaware they are actually half-brother and sister with the same dad.
In the debut Michael figured this out talking to Jennifer about their background. His key clue seemed to be when Jennifer mentioned her dad was in Vietnam with half his foot blown off, a fact Michael had known about his dad. He connected the dots, although he did not reveal these suspicions to his sister.
Link
HERE
They probably told him.