Cinema doesn't come more distressing than Gaspar Noé's unsparing drama.
Both feted and hated at the 2002 Cannes Film Festival - where it prompted walkouts from even that hardened arthouse crowd - it is not to be approached flippantly. This is a brutal, disturbing piece of work.
"There are no bad deeds, just deeds," says a character in the opening scene, calling to mind Oscar Wilde's assertion that "there is no such thing as a moral or an immoral book. Books are well written or badly written." It's a salient quote for a movie that shocks with its explicit depiction of sexual violence and murder.
Certainly the rape scene, which has so offended many viewers, is the most uncomfortable few minutes you'll ever spend in a cinema (even counting Martin Lawrence movies). Not that the preceding 40 minutes will be easy viewing either.
From the off Noé attacks the audience, his restless, revolving camera spinning over a crime scene - the aftermath of a (literally) breathtaking assault.
The action then spools backwards, "Memento"-style, tracing how Pierre (Albert Dupontel) and Marcus (Vincent Cassel) were driven to their extreme actions.
The scenes play out in long, uninterrupted takes - a feat of impressive technical and astonishing acting prowess - and we discover more about their relationship with each other and the beautiful Alex (Monica Bellucci).
Don't see this if you are easily scared or offended. "Irréversible" is a terrifying film - a raw dose of fatalism, which suggests not only the futility of revenge, but perhaps of existence.
"Time destroys all things," says an unnamed man, nailing the theme. It won't destroy the memory of this.
In French with English subtitles.