The pair have previously spoken publicly about the claims, denying they are anything more than good friends.
However, according to reports, the duo have been spotted sharing a kiss while training for the BBC dance show.
“They have been seen kissing, canoodling and even snogging while training,” an insider reportedly told The Sun.
“It’s still very early days and they are not officially dating or in a relationship, but there’s a real chemistry and attraction between them.
“Everyone is talking about it backstage and they are desperate for them to become a couple.”
However, despite both Mollie and AJ remaining adamant they were not secretly dating, the source revealed there were worries their relationship would not last past the show.
Mollie King records Aj Pritchard change his t-shirt after claiming the pair aren’t an item on This Morning [Instagram]
“But only time will tell if this is a romance that will only exist inside the Strictly bubble or something they’ll carry on with after the show,” they continued.
“He is much younger than her and Mollie tends to go for older, more mature men.”
The Strictly Come Dancing pair recently opened up about their ‘relationship’ during an awkward appearance on This Morning, and attempted to squash romance speculation.
Discussing a potential fling, Vanessa White’s pal explained: “No, we’re not together…no, we’re not. We get on so well and I think that that’s maybe why there’s these rumours.”
“We’re literally like best friends, we spend so much time together, we’re training 12 hours a day, and I still love spending every minute with him.”
AJ simply told Phillip Schofield and Holly Willoughby: “I’m single!”
OK! Online has contacted Mollie’s reps for a comment.