I really like the 1968 movie, Oliver, but I always thought there was something a little creepy about the singing voice of Mark Lester in the title role. Some time ago in an interview, Mr. Lester admitted that he'd been dubbed, though he didn't say by whom. And maybe now we know why he didn't say: It was a girl.
By the way, the current DVD release of Oliver is a good transfer. For years, we had Beta and VHS versions that were made off a poor quality negative that was poorly color-corrected, awkwardly cropped in places…and which actually had one reel of the film (about ten minutes) printed mirror-image, reversing left and right. The Laserdisc release finally got it right and the DVD continues that tradition.