It looks like "Gotham's" proto-Joker, Jerome Valeska (Cameron Monaghan) is getting ready for a serious face-off in "Smile Like You Mean It," tonight's episode of Fox's crime drama series, at least judging from a behind-the scenes photo posted on Sean Pertwee's official Twitter account earlier today.RELATED: Gotham EP On Harley Quinn’s Season 3 Arrival, Season 4 Importance

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The actor, who plays Bruce Wayne's butler Alfred Pennyworth on the show, praised the "geniuses" behind the show's gruesome yet compelling prosthetic makeup, likening their work to that of the legendary horror makeup artist Michael Maddi, whose screen credits include "Friday the 13th: The Final Chapter," "Scanners II: The New Order," and "Home Alone 2: Lost in New York."

Pertwee also tags Monaghan in his tweet (although its difficult to make the actor out under all the extreme-face-lift prosthetics) and warns fans to "miss this at your peril."

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Returning Monday at 8 p.m. ET/PT on Fox, “Gotham” is set in Batman's home city back before the Dark Knight Detective started his nocturnal patrols and stars Ben McKenzie as Detective Jim Gordon, David Mazouz as young Bruce Wayne, Sean Pertwee as Alfred Pennyworth, Camren Bicondova as young Selina Kyle, Donal Logue as Harvey Bullock, Robin Lord Taylor as Oswald Cobblepot, Cory Michael Smith as Edward Nygma, Morena Baccarin as Leslie Thompkins and Jada Pinkett Smith as Fish Mooney.