A poster has been released for The Batman, which contains a secret message only visible under a blacklight.

The film, which is out in March, sees Robert Pattinson play Bruce Wayne, while Paul Dano stars as the villainous Riddler.

A fan was able to spot the message, written in the voice of the Riddler, on a recently released poster for the DC Comics film.

The poster sees Batman and Catwoman (Zoë Kravitz) pictured before an orange background, with a Riddler symbol also visible on the page.

Twitter user @nervatel shared a photo of the revealed words on the back, explaining: "Co-worker got a blacklight."

Alongside strange symbols, the words "you are part of this too" and "find out why" can be discerned in red lettering.

Fans have decoded the symbols as saying: "You are the winged rat."

The Batman also features a starry supporting cast that includes Colin Farrell as Penguin, Kravitz as Catwoman and Andy Serkis as Alfred.

Pattinson recently admitted that his desire to play Batman shocked his agents, who had assumed that the actor only wanted to portray "total freaks".

The film is out in cinemas on 3 March.

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