There have, so far, been three Deadwood lady cast members who've appeared in Lost
On Deadwood: she plays Calamity Jane, a frontierswoman (see Wikipedia) in league with Wild Bill.
On Lost: she is in the episode Not in Portland, as Rachel, Juliet's sister whom Juliet has been experimenting fertility drugs on.
On Deadwood: she plays Trixie, a prostitute at The Gem Saloon.
On Lost: she is in the episode Every Man for Himself and The Glass Ballerina , as Colleen, one of The Others. Her character was shot by Sun.
On Deadwood: she plays Joanie Stubbs, a hostess who takes care of the girls/prostitute at The Bella Union.
On Lost: she is in the episode Every Man for Himself and The Long Con , as Cassidy, the woman from Sawyer's flashback. She is the woman Sawyer has conned.
Deadwood is currently airing Season 3 (the last Season) Tuesday nights on HBO Asia.
Lost is running seasons on AXN Asia and Studio23 regularly.
Original Airing: March 2004 – August 2006