But according to Schumacher, Kilmer "dropped us at the eleventh hour".
"He wanted to do Island of Doctor Moreau because Marlon Brando was going to be in it," the director said.
Perhaps as a result of Kilmer's last minute withdrawal, Schumacher later slammed the actor in the press, telling Empire magazine: "Val is the most psychologically troubled human being I've ever worked with".
"The tools I used working with him - tools of communication, of patience and understanding - were the tools I use on my five-year-old godson. Val is not just high-strung. I think he needs help."
EVERYONE WAS OBSESSED WITH ARNIE
Arnold Schwarzenegger was by far the biggest star on set and he was paid accordingly, pocketing $US25 million to play Mr. Freeze.
The Terminator star's role in the film caused a media frenzy at the time and the paparazzi were charging big bucks for every picture they were able to snap of the actor in costume.
"I had the security people all over the stage clearing people out who had cameras on them," producer Peter MacGregor-Scott told The Hollywood Reporter.
"They [the paparazzi] were getting $10,000 for a picture of Arnold. And we had a fabric tent around him, when he would walk from his trailer to the stage."
Some of Schwarzenegger's famous friends would occasionally visit the set, including Jon Bon Jovi who came bearing gifts.
"He brought Cuban cigars for Arnold," actor Stogie Kenyatta told THR, "so Arnold had them colour it white so he could smoke it in the scenes."
ALICIA SILVERSTONE WAS FAT-SHAMED
The Clueless star was just 19 years old when she signed on to play Batgirl in the movie.
But despite her young age, the press were just as harsh as ever and mocked Silverstone's weight before filming started.
An Entertainment Weekly article from 1996 described her appearance at that year's Oscars as "more Babe than babe".
And it wasn't much better on set.
Batman & Robin storyboard artist Tim Burgard admitted to The Hollywood Reporter that he poked fun at the star's alleged weight struggle.
"I heard that she was in the costume department being synched into a corset to fit into what they were going to try to do the costume," Burgard said.
"So I did a cartoon of what I thought that looked like. ... I did it as a movie poster, Clueless 2: The Casting of Batgirl. It was a private joke, just the guys in the art department."
Someone made a copy of the "private joke" though and it quickly spread behind the scenes of the movie.
"Luckily for me, I never signed it," Burgard said, "So I got to keep working".
ARNIE'S COSTUME NIGHTMARE
It took a team of 11 people four hours each day to transform Arnold Schwarzenegger into Mr. Freeze.
At first the actor said he was willing to shave his head for the role, but at the last minute he told his longtime makeup artist Jeff Dawn that he wanted to wear a bald cap instead.
Dawn did his best to ignore Schwarzenegger's change of heart and grabbed the hair trimmer anyway.
"He's looking at me with this big s**t-grin smile, like, 'Jeff, go ahead! I dare you'," Dawn told THR.
"And I turned it off and put the shaver back, thinking, OK, I'm not going to go this route. I'm glad I didn't to this day."
Part of the costume for Mr. Freeze included a blue LED light which Schwarzenegger had to wear inside his mouth, and it caused the actor a number of headaches on set.
"When you put it in Arnold's mouth, Arnold's saliva would creep into the seams of this thing and attack the batteries," Dawn said.
"The batteries would immediately start disintegrating and start putting out battery acid into Arnold's mouth."
Schwarzenegger was not impressed and would yell, "It tastes like s**t! What's in my mouth?"
THE TWO MAIN MEN ARE SORRY
Both director Joel Schumacher and Batman himself, George Clooney, have apologised to fans for making such a bad movie.
"Look, I apologise," Schumacher told Vice when asked about Batman & Robin.
"I want to apologise to every fan that was disappointed because I think I owe them that."
Spare a thought for the director though because it's not as if he walked away untarnished from the movie, "After Batman & Robin, I was scum," he said, "It was like I had murdered a baby".
As for Clooney, he told talk show host Graham Norton that the movie was "a disaster" and said, "I always apologise for Batman".
"Let me just say that I'd actually thought I'd actually destroyed the franchise until somebody else brought it back years later and changed it," he said.
"I thought at the time that this was going to be a very good career move. It wasn't."
BATMAN & ROBIN RUINED A BIG OPPORTUNITY FOR CHRIS O'DONNELL
Chris O'Donnell played Robin in both Batman Forever and Batman & Robin. But the latter was such a dud that plans for a Robin spin-off movie were ditched.
"They were going to do one back in the day," Chris told Access Hollywood.
The movie was going to be called Nightwing, but sadly it never eventuated.
"[Batman & Robin] was such a bomb, they were like, 'Scrap that!'" O'Donnell said.
