"I've done bits and pieces of silent movie playing in the past, mostly using silent shorts including another Buster Keaton one and some Charlie Chaplin shorts.
"Most of the ones I've done have been around 20 minutes.
"I've always wanted to do this film because it's the major one."
Although with the opportunity, Gilbert is faced with a dilemma.
"You see, the movie is set during the American Civil War of 1861 when the North and South were at war over slavery.
"The film, however, doesn't say so - there is no mention of slavery, not one black person appears, and the hero and heroine get caught up in the war, they fight for the wrong side, in an amazing series of visual gags.
"Despite that, they become increasingly lovable, and so we really want them to live happily after."
Inspired by traditional African American jazz and blues, regarding Ray Charles as one of his main teachers, you will hear a lot of African American influenced music in Gilbert's accompaniment.
"It will be mostly improvised but drawing on several styles.
"There will be a bit of white country music, Willie Nelson stuff among the African American stuff.
"At the beginning and end I'm going to play music based on Duke Ellington's compositions because it has the grandeur you want when the locomotive and railroad are such obvious symbols for the struggles involved when searching for the Promised Land – it's a symbol for America's progress.
"I've reserved the very best music for The General itself.
"There will be plenty of enjoyable plagiarism, with the music based on many artists.
"I want to make the music as enjoyable as possible, by paying homage to those wonderful African-American piano traditions from the time of the Civil War and onwards, mostly improvising within early styles."
To prepare for playing 75 minutes straight, Gilbert has blocked the music into segments.
"Some will be very short – five seconds or so, and some blocks are quite long where there are extended fight scenes, one which is seven minutes long."
"I'll have a sheet of themes but I don't want the music to distract from the action.
"The music shouldn't be prominent, it's all about the film.
Gilbert is getting plenty of practice in between now and the showing on June 13, watching The General every day in preparation.
"I want to know the film backwards so that I always know what is coming next.
"I also want to experiment different things with different scenes and match the mood of what the main characters are up to."
His introduction to film music came from his mother who was the silent movie pianist in the small town or Tuai in the Te Urewera.
Each time a movie came in, often by horse, Gilbert's mother would play the music for the film on the day it arrived.
"She was the only silent movie pianist in the whole area.
"She knew a bunch of cowboy songs and they would get a thrashing from her as it was pretty weird having a silent movie without music."
Looking forward to playing, Gilbert said, "The real fun of it is when you're playing and the audience laughs and you feed off each other."
The film is being shown at St Peter's Hall on June 13 at 5.30pm.
Door sales are $10 with all proceeds going towards The St Peter's Hall Renovation Fund.
