Reports suggest that the 20-year-old 'Wrecking Ball' singer has been getting close to the music producer, 24, in recent weeks.
This weekend, Miley was photographed in Mike's arms shortly after she delivered a performance at the iHeartRadio Music Festival in Las Vegas on Saturday (21 September).
Also, famed photographer Terry Richardson posted some racy pictures of Miley and Mike on his Tumblr account, revealing that he had been photographing the pair in the studio. In one shot, Miley, who is wearing a white crop top and knickers, is sticking out her tongue and wrapping her arms around Mike.
Mike - real name Michael Len Williams II - has been working close with Miley since the beginning of this year, as he helped to produce most of the tracks off her latest studio album Bangerz.
Her lead single 'We Can't Stop' was produced by Mike and released June this year. Miley has also posted plenty of photos of herself in the studio with Mike.
News that Miley is moving on comes just days after her ex-fiancé Liam was pictured kissing actress Eiza González.
Last week, representatives for both stars confirmed that the couple's engagement was over after months of speculation. Liam is also thought to have started moving his belongings out of the pop singer's Los Angeles home.
Reveal has contacted Miley's rep for a comment.