The Cheltenham Gold Cup-winning jockey rode over 1,000 winners in a long career in the saddle which finished in June with a success at Uttoxeter.
Grand National winner Timmy Murphy, Classic hero Ted Durcan and TV presenter Luke Harvey are also among the 16 riders this year in the charity event.
Thornton rides the Les Eyre-trained Detachment, who finished fourth last year for Ollie Pears.
“I think the draw’s been kind to me – Les has been a good pal of mine for a long time,” said Thornton.
“It will be a great day. I think they are hoping to take the money raised to over £1 million for the Injured Jockeys Fund and Northern Racing College and to be fair, Gibbo (Dale Gibson) puts in an awful lot of work.”
On his race preparation, Thornton added: “I’ve still got another couple of pounds to lose. I went up to about 11st 7lb and I’ve been in proper training for the past fortnight.
“I’ve been running every day, getting fit, just like I used to. People are telling me it’s only a mile, but it’s two as you’ve got to get to the start!
“I had a ride out for Seamus (Mullins) the other day and it was hanging like a gate and by the time I got off, my left calf and my left thigh were in bits.
“You use muscles that you use for nothing else and as I hadn’t been riding out, I’d forgotten how much it gets to you. I’ve had plenty of rides since and I’m pleased to say it’s like riding a bike.
“I think he should have a chance, he nearly won it last year and is 1lb lower – I just wish I wasn’t drawn as far away from Timmy (Murphy) as I am as I used to follow him knowing he’d be in the right position!”