Peter Sarsgaard joins 'The Batman' but who will he play?

Peter Sarsgaard is set to join the expanding cast of director Matt Reeves' The Batman, it's been confirmed.

Reeves himself dropped the news, via Twitter, with a gif of the actor and 'Oh... Hi, Peter...', followed by a tiny bat emoji.

However, who he will play has not been confirmed – though online rumour-mongering appears to be fixated on him playing Harvey Dent, aka Two Face, the former Gotham City District Attorney who goes insane after being disfigured by acid.

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He was last seen in the Batman movies played by Aaron Eckhart in The Dark Knight.

Whether he'll end up in that role remains to be seen, but Reeves is filling up his comicbook reboot with a host of famous faces and equally famous characters from the DC canon.

Robert Pattinson is paying Bruce Wayne, alongside Zoe Kravitz's Selina Kyle (aka Catwoman), Paul Dano as The Riddler and Colin Farrell as The Penguin.

Jeffrey Wright will be picking up the mantle as Commissioner Jim Gordon, Andy Serkis will play Bruce Wayne's butler and confident Alfred, while John Turturro is playing Gotham's crime linchpin Carmine Falcone.

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Sarsgaard, who is married to actress Maggie Gyllenhaal, was most recently seen in the drama's The Sound of Silence and Mr Jones.

Filming on The Batman is expected to start in the New Year, with a release date slated for June 25, 2021.