Show bosses recently confirmed that one character will be killed off when Emmerdale goes live for its 40th anniversary next month, leading to speculation over which village resident is about to meet their maker.
Thomas, who plays Adam Barton, told Digital Spy that it will be sad to say goodbye to the actor in question.
He explained: "Without a shadow of a doubt we'll miss this person - of course. When someone does leave, it's definitely a big thing for us because we all work so closely on Emmerdale and we all have so many scenes together."
The 25-year-old also promised that viewers can expect big things from the special live broadcast.
He said: "It's definitely going to be nerve-wracking, but once we've done it, we're all going to be so proud that we've pulled something off that's as spectacular as this episode is going to be. It's just going to be momentous afterwards.
"It's definitely worth it. I've got about one line - they don't trust me!"
Emmerdale airs weeknights on ITV1.