Strictly's Kai Widdrington was overhead telling AJ Odudu he 'loves' her amid romance rumours.
The professional dancer, 26, and the TV presenter, 33, are partners on this year's series and it was claimed they have grown close during their gruelling hours of training together and have 'really hit it off'.
Each week, the show releases the 'secret mic' audio which reveals what the contestants say to each other on the dancefloor.
Affectionate: Strictly's Kai Widdrington was overhead telling AJ Odudu he 'loves' her amid romance rumours
Viewers are unable to hear it in real time due to Dave Arch and his orchestra.
In a clip shared on BBC's Strictly Instagram, Kai could be heard praising AJ for her efforts after their The Bodyguard-inspired American Smooth on Saturday.
He could be heard saying: 'Aww, I love you! I love you so much!'
It comes after a source told The Sun that 'sparks are flying between the pair' and that 'romance is 100 per cent on the cards'.
Close: The professional dancer, 26, and the TV presenter, 33, are partners on this year's series and it was claimed they have grown close during their gruelling hours of training together and have 'really hit it off'
Kai is single after splitting form his dancer girlfriend of five years Giulia Dotta, 29, earlier this summer.
Meanwhile AJ recently said she has unsuccessfully tried dating apps after struggling to find a partner, adding: 'I just don't meet anyone, aside from TV programmes I've done'.
A source said: 'Everyone backstage is talking about the sparks flying between AJ and Kai. It's very passionate and intense whenever they're together.
'They're both single and have really hit it off and everyone on the show is saying it's only a matter of time.
Performance: Each week, the show releases the 'secret mic' audio which reveals what the contestants say to each other on the dancefloor.
'They're always laughing and flirting — romance is 100 per cent on the cards.Kai is totally AJ's type. He's got loads of banter and he's been blown away by her, too.'
Representatives for AJ and Kai have been contacted by MailOnline for a comment.
It comes after AJ posted a picture of Kai's six pack to social
