The best part of the movie, I thought. The rest of it creeped me out.

from wiki:

Redden, then 15, earned his role in Deliverance during a casting call at Clayton Elementary School in Clayton, Georgia. To add authenticity and humor to the film, the filmmakers found Redden to fit the look of the inbred and mentally retarded banjo boy called for by the book, although Redden himself is neither. His distinctive look was enhanced using special makeup.

In his famous scene, Redden plays the instrumental "Dueling Banjos" opposite actor Ronny Cox on guitar. It is noted for foreshadowing the film's theme: exploring unknown and potentially dangerous territory. Redden could not actually play the banjo. A local musician, Mike Addis, reached around from behind Redden; this was disguised using careful camera angles.

Jon Voight claimed Redden "was a boy who had a genetic imbalance – a product of his mother and his brother, I think. He was quite amazing, a very talkative fellow."[1]

Redden also appeared in Tim Burton's 2003 film Big Fish. Burton was intent on getting Redden, who hadn't appeared in a film since Deliverance, to play the role of a banjo-playing welcomer in the utopian town of Spectre. Burton eventually found him in Clayton, Georgia, where Redden worked as a cook, dishwasher, and part-owner of the Cookie Jar Café.

Some day I will have to take a trip to Clayton and visit the Cookie Jar Cafe and look him up if he is still alive.

.
.
.
Next time I watch it, I'll have to keep an eye out for him.
.
.
.

I've yet to see Big Fish. Since it's recommended by you, MFM, I'll make a point of it. I hope that's a wise decision.