“Well, as you know, when Singing in the Rain came out, for generations of people, [Gene Kelly] swinging around that lamp post and slapping in that water, and singing…it’s one of the most euphoric moments we’ve ever seen on film. So when I had to come up with something for this sequence, which involved my character in a very brutal situation, that’s when he’s happiest. So Singing in the Rain just popped out. I just started singing it, and [Stanley] Kubrick bought the rights and we redid the whole thing and incorporated it.
A footnote to that is that a year afterward, when the film had been out and it was a big hit, I was invited to come to Hollywood by Warner Brothers. I came out and it was very nice to meet everybody. I had never been to Hollywood before. And some guy who was my minder said, ‘Hey, there’s a party in Beverly Hills tonight, Malcolm. Do you want to go, there’s going to be lots of stars there?’ And I went, ‘Yeah! I would love to!’ I was like a kid in a candy store. And we go and he said, ‘Hey, you won’t believe this. Gene Kelly’s here. Would you like to meet him?’ And I went, ‘Oh yeah!’ (laughs)
So he had his back to me and he tapped him on the shoulder and said, ‘Gene, I’d like to introduce you to Malcolm McDowell’ and he looked at me and…then turned around and walked off.
But you know, I totally got it. I totally understood. I took his glorious moment and put a different spin on it. I guess I kind of ruined his moment in a way. But of course, it was an homage to him, because it was so amazing. And so indelible in me as a person, that I blurted it out and started singing it [while filming the scene].”
–Malcolm McDowell (via)