In 2008, Horgan appeared in Hedda, a modern updated version of Hedda Gabler, directed by Carrie Cracknell[5] in which she played the lead character to favourable reviews; reviewer Charles Spencer in The Daily Telegraph wrote that she was "especially fine as a glamorous, bob-haired Hedda, ... using sex... like a shrimping net".[6]
From 2013 to 2015 she joined Sean Holmes ten-member Secret Theatre company at the Lyric Hammersmith,[5][13] which experimented with improvisational techniques towards drama. For some performances, a cast member's name was chosen from a hat by an audience member to be the show's protagonist; then, he or she would be "given a series of increasingly impossible acts to accomplish" which could involve such activities as complex dance routines, wrestling, singing and improvisation, according to one account.[14][15] She performed with the ensemble for two years to positive reviews.[16] In an extended interview in Exeunt Magazine, she described her work at Secret Theatre as giving her "freedom to play".[17]
In 2015, she appeared in The Mother at the Ustinov Studio in Bath.[18] In 2017 she appeared in Cellmates at The Hampstead Theatre directed by Edward Hall. Paul Taylor in The Independent wrote[19] "Cara Horgan is delectable in a double as the Russian maid who duets with Bourke in his hammy renditions of “Danny Boy” for his captors and as the wife in a CND couple who have an inconvenient marital meltdown while helping Blake on his first night outside"
^ abcd"Casting announced for THE MOTHER by Florian Zeller", LondonTheatre1News.com, 20 April 2015. Retrieved 18 July 2015; "Cara Horgan's theatre credits ... Secret Theatre ... School For Scandal...Pains of Youth ...The House of Special Purpose... and Hedda Gabler ... film credits include The Boy in the Striped Pyjamas ... and The Libertine..."
^Charles Spencer, "Updated Hedda is off-target", telegraph.co.uk, 3 September 2008. Retrieved 17 July 2015. "... Cara Horgan is especially fine as a glamorous, bob-haired Hedda ... using sex... like a shrimping net."
^Paul Taylor, Theatre review: Secret Theatre – Show 3, independent.co.uk, 28 October 2013. Retrieved 17 July 2015. "...monstrously ambitious prison governor (superb Cara Horgan)..."
^Dan Hutton, Freedom to Play: Q&A and Interviews, exeuntmagazine.com, 1 October 2013. Retrieved 18 July 2015. "...according to Cara Horgan, asks "the audience to put their own interpretation or their own understanding of things on the work they're seeing...."