Question: Which Irish actor stars in Untogether, an upcoming American drama film?

Context paragraphs:
Phantom Thread: Phantom Thread is an upcoming American drama film, set in London's fashion world in the 1950s, shot, written and directed by Paul Thomas Anderson.  The film stars Daniel Day-Lewis, Lesley Manville, Richard Graham, Fraser Delaney and Vicky Krieps.  It is reportedly Daniel Day-Lewis's final performance in a film, following four decades in the profession.  The music will be composed by longtime Anderson collaborator and Radiohead member Jonny Greenwood.  The film is set to be released on December 25, 2017.

Chappaquiddick (film): Chappaquiddick is an upcoming American drama film directed by John Curran and written by Taylor Allen and Andrew Logan.  The film stars Jason Clarke, Kate Mara, Ed Helms, Bruce Dern, Jim Gaffigan and Taylor Nichols.  It was screened in the Gala Presentations section at the 2017 Toronto International Film Festival.  It is scheduled to be released on December 8, 2017 by Entertainment Studios.

What They Had: What They Had is an upcoming American drama film written and directed by Elizabeth Chomko.  It stars Hilary Swank, Michael Shannon, Robert Forster, Blythe Danner, and Taissa Farmiga.  The film will be released in the United States by Bleecker Street.

Jamie Dornan: James "Jamie" Dornan (born 1 May 1982) is an Northern Irish actor, model, and musician.  He played Axel von Fersen in Sofia Coppola's "Marie Antoinette" (2006), Sheriff Graham Humbert in the ABC series "Once Upon a Time" (2011–2013), serial killer Paul Spector in the BBC Two and RTÉ One crime drama series "The Fall" (2013–2016), and Christian Grey in the "Fifty Shades" franchise (2015–present).

Benji (upcoming film): Benji is an upcoming American drama film written, co-produced and directed by Brandon Camp.  The film is a reboot of the 1974 film of the same name.  It stars Gabriel Bateman and Darby Camp.  Jason Blum is serving as a producer through his Blumhouse Productions banner and Universal Pictures is distributing the film.

Same Kind of Different as Me (film): Same Kind of Different as Me is an upcoming American drama film directed by Michael Carney and written by Ron Hall, Alexander Foard and Michael Carney.  It is based on the book of the same name by Ron Hall, Denver Moore and Lynn Vincent.  The film stars Greg Kinnear, Renée Zellweger, Djimon Hounsou, Olivia Holt, Jon Voight, and Stephanie Leigh Schlund.  The film is scheduled to be released on October 20, 2017, by Pure Flix Entertainment.

Flower (film): Flower is an upcoming American drama film directed by Max Winkler and written by Alex McAulay.  It stars Zoey Deutch, Kathryn Hahn, Adam Scott, Dylan Gelula, and Tim Heidecker.  It premiered at the 2017 Tribeca Film Festival.

Wonder Wheel (film): Wonder Wheel is an upcoming American drama film written and directed by Woody Allen.  It stars Jim Belushi, Juno Temple, Justin Timberlake and Kate Winslet.  The film is set in a late 1950s amusement park at Coney Island.

Burden (film): Burden is an upcoming American drama film, inspired by true events.  The film will be produced by Robbie Brenner and It will be written and directed by Andrew Heckler.  The film stars Garrett Hedlund, Forest Whitaker, Tom Wilkinson, Tess Harper, and Usher Raymond IV.

Untogether: Untogether is an upcoming American drama film directed by Emma Forrest, which is her directorial debut.  The film stars Jamie Dornan, Ben Mendelsohn, Lola Kirke and Jemima Kirke.  The film began production in October 2016.

Supporting paragraphs: Untogether Jamie Dornan
Answer: Jamie Dornan