Simon, 40, has played Steve McDonald since 1989, but it's thought that he's taking some time away from the soap due to illness.
It's also been confirmed that Stuart Blackburn will step down as producer and be replaced by Kate Oates, who currently produces Emmerdale.
Stuart has been working on the show since 2013, and it has been alleged that he's the reason stars including Michelle Keegan [Tina McIntyre] and Julie Hesmondhalgh [Hayley Cropper] quit the show.
A source told The Sun: "This announcement will massively boost cast morale in the run-up to the live episode as Stuart was becoming unpopular with them, the writers and the production.
"The announcement ahead of the live episode was timed to disguise the fact he's leaving when ratings are down and the show's in really bad shape."
Following the news that Kate is joining Corrie, fans took to Twitter to express their relief.
In three years, Kate has been responsible for some of the most exciting story lines to have ever been played out on Emmerdale.
A friend told the Mirror: "There is no one more passionate about soaps than Kate, she will throw herself into the new job and Corrie will really benefit from her new ideas."
Taking over from Kate on Emmerdale will be Iain MacLeod, currently story producer for Channel 4's Hollyoaks. The changes will come into effect in the new year.