Robert Powell was supposed to be Judas....
... until Zeffirelli saw his eyes and finally Ian Mc Shane did Judas. Watch Powell with a shawl on and without the "Jesus" wig on (even his moustache and beard are different) :
http://fotolog.terra.com.mx/inca:166
His hair was chemically straightened, his features enhanced. Apparently, when Powell came out on to the set the crew gasped.
"I looked in the mirror and realised I was looking at the image of Jesus I had retained from my childhood. It was the image English people recognise as Christ: Holman Hunt's Light Of The World. Except I wasn't blonde. But my silhouette could only have been of one man- Christ. It was extraordinary".
There's a thin gap between skepticism and cynicism