"I'm still in the process of talking to Matt Reeves who is the director and wrote the script and wrote a really, like really beautiful, dark, moving script. Really gorgeous," Farrell said on Wednesday.
"He has a real love for it Matt, so we're still in the process of just finishing designing the aesthetic of the character," he continued in reference to how his Penguin look is still in development.
Farrell joked that he has about three weeks before he starts shooting, which should give him enough time to gain weight for the role. The Penguin is normally portrayed as short and overweight.
The Batman, set to hit theaters on June 25, 2021, will also star Robert Pattinson as Batman, Zoe Kravitz as Catwoman, Andy Serkis as Alfred Pennyworth, Paul Dano as The Riddler and Jeffrey Wright as Commissioner Gordon.
Farrell will next be seen in crime drama The Gentlemen from director Guy Ritchie. The film opens in theaters on Friday. Matthew McConaughey, Charlie Hunnam, Henry Golding, Michelle Dockery, Jeremy Strong, Eddie Marsan and Hugh Grant also star.