The pair, who danced together on last year's series of Strictly, have been spotted out together.
According to The Sun, the couple were seen kissing in Manchester and "it wasn’t just an innocent quick peck."
An onlooker told the tabloid: “This was Mollie and AJ properly going public with their romance. They were all over each other all night and kissing and cuddling. They only had eyes for each other and they were properly going for it.
“They didn’t leave each other’s side.”
Meanwhile, an insider told heat: "Now that Strictly's over, Mollie and AJ don't are who knows about them - they just didn't want to take away the focus while they were dancing."
They added: "They've rally fallen for each other and get on so well."
The Saturday's singer Mollie and Strictly pro dancer AJ were said to have grown close during 2017's series.
After a lot of speculation - including teasing from their fellow celebs - ahead of the final an insider claimed to The Sun: "They have been seen kissing, canoodling and even snogging while training.
“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."
As for Mollie and AJ themselves, they've always been coy about the status of their relationship.
Asked if they were a couple outside of the ballroom, AJ told the Daily Star newspaper earlier this year: “That question will have to stay on everyone’s lips! But she is gorgeous and has the sexiest bum on the show.
“Time flies when we are together. We are always laughing."
Meanwhile, speaking to the Metro newspaper about the rumours, Mollie said she wouldn't say no if AJ asked her out.
"I can't tell you that! I have to see if he does! Who knows?" she said.
At the start of the series, Mollie said she was single and having "fun" on the show.
"There’s always going to be rumours on Strictly, that’s inevitable," she said. “The main thing is that people can see how well we get on. We have so much fun doing this."
Admitting they were "comfortable" together, Mollie added: “AJ and I are physically very close all day and that’s such a huge part of the dancing.
“We don’t even think about it. We’re really close friends now.”
Strictly Come Dancing was won by Joe McFadden during December's final.