Strictly's Nadiya Bychkova and Kai Widdrington have remained tight-lipped since reports of their romance began circulating last year, but the couple have now made a surprising confession about the relationship.MORE: Nadiya Bychkova and Kai Widdrington have flirty exchange – and fans have noticedThe couple attended the opening night of Matthew Bourne's thriller play The Car Man at Royal Albert Hall on Thursday and told MailOnline that they are "very happy".WATCH: Kai Widdrington and Nadiya Bychkova share romantic dance videoNadiya, 32, then added: "I think you can tell yourself."READ: Kai Widdrington and Nadiya Bychkova continue to fuel relationship rumours with new videoRELATED: Dan Walker reacts to Nadiya Bychkova's reunion with Kai Widdrington as they perform together for special reasonNadiya looked stunning for her and Kai's rare night out, choosing to wear a blue satin dress with laced hem detail. The mother-of-one opted to wear her hair straight and wore a stunning pair of lace ankle boots, that perfectly matched the dress.