Duffy told RTÉ that alter ego Ciaran McCarthy will steal from his restaurant after losing money on the horses.
"Ciaran gambles away all his wedding money and then gets into trouble with Michelle (Kym Marsh) and then he robs a bistro to get his money back and then he gets caught," he said. "It's great."
The 37-year-old, who is starring in an upcoming Irish theatre show, believes that his autumn return has challenged him as an actor.
The Boyzone singer added: "I get loads of opportunity to show all my flair from all different angles."
Duffy quit Corrie permanently in September after nearly ten years in Weatherfield on-and-off.
> Keith Duffy: 'Producers say I always have a job on Corrie'