Deadline broke the news of Monaghan's casting, though it's unknown the part he will be playing in the sci-fi film.
We do know that Tron: Ares will follow Leto's character Ares on a journey “from the digital world to that of humans,” thanks to Deadline's report. Joachim Rønning has been a part of the Disney family for a number of years now, directing Pirates of the Caribbean: Dead Man Tell No Tales and Maleficent: Mistress of Evil. He will direct Tron: Ares as well. The film was penned by Jesse Wigutow and Jack Throne. Rounding out the Tron film's main cast are Evan Peters, Jodie Turner-Smith, and Greta Lee.
Deadline indicates that production on the Tron film was eyeing an August start, but the SAG-AFTRA strike will now likely delay those plans.
Tron: Ares will be the third film in the sci-fi series. The first film was released in 1982 and starred Jeff Bridges as Kevin Flynn. A sequel, Tron: Legacy, was released in 2010 and starred Garrett Hedlund and Olivia Wilde. It grossed over $400 million during its theatrical run but there wasn't any movement on another live-action sequel until recently.
Cameron Monaghan is most known for his role on the Emmy-winning series Shameless, but he also lent his voice and gave his likeness to Star Wars Jedi: Fallen Order and its sequel, Survivor. He's been acting for years, with one of his earliest roles coming in Adam Sandler's Click. Monaghan also had a role in the Gotham series as the set of twins Jerome and Jeremiah Valeska.