"There was a sex scene in it, and I was very nervous because I'd never done a sex scene," Farrell said.
"I went up to the director, Joel Schumacher, and I had a dressing gown on and nothing underneath. I was obviously so nervous that I lost my mind for a second because I opened my dress and I said, 'Is it a bit...?' Because, like most men, I had what you could refer to as 'retro bush.'"
Schumacher was slightly taken aback so Farrell went to the hair and makeup department, borrowed a beard trimmer and got to work.
"I went into my trailer, I got a bin and I put it [below his groin]," he told Ellen.
"I was nervous and I trimmed the right side a little bit, and obviously I had to match it, so I trimmed the left. But I overshot the mark by a little bit, so I had to get back in and approach the right again.
"I overshot that, and at this stage, I was sweating. I went back in and reapproached the landing on the left, and then I looked down and I had a little landing strip - a lovely, lovely little landing strip."