Middleton's character Ashley Thomas, who has recently suffered turmoil as a result of his marriage break-up, is expected to play a part in the rural serial's birthday week next month.
The actor told Inside Soap: "As you know, we're doing a live episode, and we're approaching it with trepidation!
"If anything goes wrong on set these days, people just turn round and go, 'I've got two words for you - live episode!'
"We don't know what's going to happen, but we've had various hints. It's terribly exciting."
Middleton's co-stars Sammy Winward (Katie Sugden) and Lucy Pargeter (Chas Dingle) have already expressed their fear over the live special.
Winward is particularly worried that she will burst into uncontrolled laughter during her on-screen wedding with Jason Merrells (Declan Macey).