In photographs obtained by The Sun, the duo were seen kissing each other at a bar in the Malmaison Newcastle, as the Live Tour stopped over in the city. Nadiya looked beautiful in a turquoise overcoat, and had a cap to mask her blonde hair, while Kai wore a green hoodie, with a black beanie and also had a backpack over his shoulders.
WATCH: Nadiya Bychkova transforms with glam makeover
The photos of the kiss come shortly after some of the cast headed to the beach and running towards the freezing cold waters earlier in the week, and the two were seen close together.
They also come after Kai and Nadiya had denied being a couple, but rumours had been sparked after the pair had been spotted together outside of rehearsal time.
Nadiya has recently become single after the Ukrainian-born dancer split from her fiancé, Matija Škarabot as they struggled to maintain their long-distance relationship.
In recent weeks, Nadiya stopped wearing her engagement ring and is no longer being followed by Matija on Instagram.
Nadiya danced with Dan on the last series of Strictly
However, the MailOnline reported that the former couple remained committed to the five-year-old daughter that they share, Mila.
Kai was previously dating fellow dancer Giulia Dotta for five years before they split. Guila's agent confirmed to the Mirror last July that the pair had called time on their relationship, but it's believed that they split several months earlier during lockdown.
Kai and AJ were subject to romance rumours
Prior to that, Kai was also the focus of romance rumours during the last series of Strictly, with fans convinced he had started a relationship with his celeb partner, AJ Odudu.
The chemistry was so much that It Takes Two host Janette Manrara even teased the pair about it during an appearance on the show, but they always denied that anything was going on.
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