<Tr> <Th> Occupation </Th> <Td> Fugitive and fake mother of Aaron Littleton </Td> </Tr> <Tr> <Th> Nationality </Th> <Td> American </Td> </Tr> <Tr> <Th> Former residence </Th> <Td> Ames, Iowa, USA </Td> </Tr> <P> Katherine Anne "Kate" Austen is a fictional character on the ABC television series Lost, played by Canadian actress Evangeline Lilly . Before the pilot was shot during the writing phase, Kate was to emerge as the leader for the survivors, motivating them to build shelter and begin considering life as permanent residents of the island, however when it was decided Jack should survive, she was a second - in - command . In this original description for Kate, she was a slightly older woman separated from her husband, who went to the bathroom in the tail - section of the plane . However, that idea ended up being used for Rose Henderson (L. Scott Caldwell) and her husband Bernard Nadler (Sam Anderson). Kate is involved in a love triangle with Jack and Sawyer (Josh Holloway) and is seen as very protective of Claire (Emilie de Ravin) and her baby Aaron . </P>

Who is the father of kate's baby in lost