Washington, Apr 4 : Bristol Palin''s former fiancé and babydaddy Levi Johnston has revealed that Sarah Palin knew he and her daughter were having sex when they lived under her roof.
In a show airing April 6, Johnston tells Tyra Banks: "I''m pretty sure she probably knew. Moms are pretty smart."
While on the show, Levi talked about his sex life on national television, reports People.
However, the show hasn't been received well by the Palin household.