Rebecca Leigh Mader (born 24 April 1977) is an English actress, best known for her roles as Charlotte Lewis in the ABC series Lost, and as Zelena, the Wicked Witch of the West, on ABC's Once Upon a Time.
Mader was born in 1977 in Cambridge, England. She worked as a model in New York City for a year, appearing in adverts for L'Oréal, Colgate and Wella Hair. She began her television career on the ABC daytime soap operas All My Children as Morgan Gordon, and One Life to Live as Margaret Cochran. She also appeared on the soap opera Guiding Light in 2003.
Mader has made number of guest appearances on television shows. In 2006, she had a series regular role of the short-lived Fox legal drama, Justice. In 2008, Mader began starring as anthropologist Charlotte Lewis on ABC series Lost. She appeared in the show from 2008 to 2009 and in two episodes in 2010. In 2011 she had a recurring role on No Ordinary Family, and in 2012 she made a guest starring appearance on the FOX science-fiction series Fringe, as Jessica Holt. Also in 2012, Mader starred in the short-lived ABC comedy series Work It.