The actor's character Andy Sugden will be among those involved in the special 40th anniversary broadcast, supporting Debbie Dingle (Charley Webb) as she gives birth to their second child.
Viewers can expect an anxious time ahead for the pair as they desperately hope the saviour baby will help their young daughter Sarah, who is seriously ill with a rare genetic disorder.
Speaking on Loose Women today (October 11), Fletcher said that he is confident the live episode will be a success, as cast and crew have been given extensive rehearsal time for the challenge ahead.
Pictured: Kelvin Fletcher on Loose Women.
Fletcher commented: "For a couple of weeks, we did a few Saturday work days and caught up on episodes so we could afford to have two weeks off not filming anything, and then we've come in most days to rehearse.
"I'm alright [about it]. Watch this, I'll probably get something wrong now on the night, but I'm really excited about it. It's like doing a bit of theatre, the buzz is there, and I'm really looking forward to it.
"Everyone's on their A-game, and reading the script, I'm a bit biased but it's going to be amazing, it really is. It's the best script I've probably read."
On Andy's role in the episode, he explained: "Amongst this live episode will be the birth of the child. I will be there hopefully, as all dads should be! [Debbie's] kind of got two male figures there, her current partner and Andy."
Emmerdale Live airs on Wednesday, October 17 at 7pm on ITV1. Get the Inside Soap magazine on your iPhone or iPad