Dublin native Cillian Murphy leads a stacked cast in Christopher Nolan's nearly three-hour epic, his lead performance hailed by early audiences as "sublime".

Murphy has collaborated with the director in multiple films, including the 2017 World War Two war drama Dunkirk, but Oppenheimer marks his first Nolan film in the leading role.

Adapted from the 2005 biography American Prometheus by Kai Bird and Martin J. Sherwin, the film immerses audiences in the story of J. Robert Oppenheimer, the World War II Manhattan Project leader and creator of the atomic bomb. The film's supporting cast includes performances from Hollywood heavy-hitters Robert Downey Jr, Emily Blunt, Florence Pugh and Matt Damon, but it's Murphy that takes the top billing.

Critics invited to the premiere have already begun singing the film's praises.

"[It's] a character study on the grandest scale," wrote Total Film deputy editor Matt Maytum, "an epic historical drama but with a distinctly Nolan sensibility."

#Oppenheimer left me stunned: a character study on the grandest scale, with a sublime central performance by Cillian Murphy. An epic historical drama but with a distinctly Nolan sensibility: the tension, structure, sense of scale, startling sound design, remarkable visuals. Wow

— Matt Maytum (@mattmaytum) July 11, 2023

Associated Press's Lindsey Bahr was similarly captivated, and called it a "truthful, concise adaptation" with "inventive storytelling and nuanced performances."

Christopher Nolan’s #Oppenheimer is truly a spectacular achievement, in its truthful, concise adaptation, inventive storytelling and nuanced performances from Cillian Murphy, Emily Blunt, Robert Downey Jr., Matt Damon and the many, many others involved —- some just for a scene.

— Lindsey Bahr (@ldbahr) July 11, 2023

Oppenheimer hits cinemas July 21st, the same day as Greta Gerwig's highly anticipated Barbie film starring Margot Robbie and Ryan Gosling. People were quick to point this out, some going as far as to insist they would attend an Oppenheimer-Barbie double feature despite the drastically different subject matters.

Double-feature or not, audiences have been urged by early reviewers to watch Oppenheimer on as big a screen as they can. Dublin's IFI will be showing the film in high-resolution 70mm, Nolan's preferred format.

Oppenheimer will release in Irish cinemas July 21st, and advance tickets are available now.