Christian Bale has revealed that the only Batman-related advice he passed onto Ben Affleck was about going to the bathroom.
The Welsh-born star, who portrayed the caped crusader in Christopher Nolan's Batman trilogy, admitted he told Ben - who will play the superhero in Zack Snyder's Man Of Steel sequel - to make sure he could go to the toilet without needing extra assistance.
"[I told him] just make sure you can take a p*** without anyone helping him because it's a little bit humiliating," he told Access Hollywood.
"I went through having to have someone help you out of the costume in order to be able to do that. That was my main piece of advice for him."
Christian reckoned that the Argo star will do the role justice.
"I wish him all the best. He's a very experienced actor and filmmaker. He'll make it his own," he said of the Oscar winner.
"It should be passed on to another actor and will be again after him."
Meanwhile, Christian said he was moved when he saw the story about leukaemia sufferer Miles Scott, who got his dream of being Batkid for a day and solve a series of mock crimes in San Francisco. The five-year-old even got a shout-out from US President Barack Obama and Ben Affleck.
"Wasn't that fantastic?" he told Vulture. "I looked on the news and I saw this headline and thought, 'What's that?' And I saw all the pictures of him running around and saving people. It's so touching."
He added: "What a wonderful day for the little fella! It's just fantastic, seeing all those people who were out there to support it. Hopefully, later on, he'll be able to look back and say, 'Oh my God, how amazing'."