According to The Sun, the two first bonded over their shared interest in working out, and their relationship took a romantic turn after a short period of texting.
An insider told the newspaper: “Mel loves a younger man and really fell for Olly when he got into shape late last year.
The two are yet to comment on their alleged romance publicly, but Melanie did previously hint at it earlier this year, when she posted a photo of them together on Instagram.
Back in December, she also revealed she was listening to his album cut ‘Flaws’, claiming his vocals “made her want to cry”.
HuffPost UK has reached out to representatives for both Olly and Melanie for comment.
Aside from rumoured developments in his personal life, 2017 has been an exciting year for Olly, touring the UK in support of his most recent album, ‘24 Hrs’ and joining the team of ‘The Voice’.
He’ll be slipping into the seat previously occupied by Gavin Rossdale when the talent show returns for its second series on ITV next year, alongside returning stars Sir Tom Jones, Jennifer Hudson and will.i.am.
The move is a particularly surprising one as Olly was previously a runner-up - and briefly co-host - on ‘The X Factor’, with Simon Cowell said to be particularly unimpressed with the star’s latest venture.