Moulin Rouge Midget. . . . . How?

I just saw Moulin Rouge. I liked it. What I want to know is: how did they make John Leguizamo so short? Some scenes it was obvious they were filming him on his knees, but in other scenes you can see him standing full-length, and it seems awefully realistic. Did they use computer animation? That seems to be the most likely scenario. If they did, what was the exact process? I’d be interested to know all of the details of how they make him look short.

A thought just occurred to me. What if John Leguizamo is actually a midget? Perhaps he’s been fooling us allthese years into thinking he is of normal height.