During her career, Siggins has shown her range in a variety of roles, playing characters from the aristocratic and modern femme fatale, and action-minded women in The Suicide Club (2000), Accidental Encounter (2008) and Shen gong yuan ling (2013), to a desperate refugee in DDU (1999) and alienated foreign queen in The Six Wives of Henry VIII (2001). Catherine has worked in Ireland and the UK in feature length films, theatre, and appeared in Lead and Guest star roles in national television series including Casualty (1999), The Last Detective (2003), and worked with award winning directors of both film and television (Mike Figgis, Ciaran Donnelly, Kieron J. Walsh, Jamie Payne). Her feature film debut was a lead role in legendary film producer Roger Corman's The Suicide Club (2000) opposite Jonathan Pryce, Paul Bettany & David Morrissey. Of her work Variety said Catherine had " a face and a voice made for the big screen", and The Hollywood Reporter said "Siggins is both a dark haired beauty and talented as she pulls off a difficult role". In 2012, she worked with Mr. Corman again in China, shooting a lead in Shen gong yuan ling (2013) (Official Selection 2013 Puchon International Fantastic Film Festival, S. Korea, and Official Selection 2013 Sitges International Film Festival, the largest fantasy and horror film festival in the world held in Catalonia, Spain).