Why else would the Batman V. Superman: Dawn of Justice Twitter account follow John Cleese unless Warner Bros. is at least considering him for a part in a DCEU movie?
It looks like that very impressive list might be getting longer, as comedy legend John Cleese just might be joining up with the DCEU starting with Justice League.
No matter what, having someone as legendary as John Cleese in a DCEU movie would be a pretty big deal and would definitely help elevate whatever movie he shows up in.
Though that is done filming, reshoots are happening, so the odds of John Cleese showing up there are slim to one.