Joe Manganiello will play Deathstroke.
The True Blood and Magic Mike actor was confirmed for the role by Geoff Johns, the recently-appointed DC Entertainment president and Chief Creative Officer. Deathstroke will appear in the as-yet-untitled solo Batman movie, though Johns would not confirm if Manganiello would appear as the character in Justice League.
It was on the London set of Justice League that footage of Deathstroke was shot, and later revealed by Ben Affleck.
The solo Batman movie – thought to be titled The Batman – is rumoured for a 2019 release, though could feasibly be out in 2018 depending on filming schedules. Justice League will be released on 16 November 2017.