The pair secretly eloped to Tybee Island, according to a detailed investigation by top American magazine In Touch Weekly - with many of the details backed up in a similar report out today by rival publication OK!.
The couple first met on the island eight years ago while filming The Last Song, and it's been an important place for them ever since. But even so, the couple were not planning to take the plunge before their trip.
'Neither Miley nor Liam planned to get married when she booked the trip to see him, but that all changed once she arrived,' a source tells In Touch. 'They felt so nostalgic and spent hours reminiscing about old times.
'They both realised the island was the ideal setting because it has such sentimental value to them.'
The spontaneous wedding was reportedly a very down-to-earth affair, which suited Miley just fine.
'Miley enjoys leading a hippie life and never wanted a big Hollywood wedding, so it all worked out perfectly.'
The bride reportedly wore a casual, long white dress and they exchanged vows on the beach, celebrating their big day over a candlelit dinner.
Backing up the report, American OK! claims that the couple have been spotted wearing matching wedding rings, with multiple witnesses insisting the duo definitely got hitched.
'The idea to elope was totally spur of the moment,' claims the publication's source. 'Liam's been filming in Savannah, and he asked Miley to visit for the long weekend. Then they realised Tybee Island, where they first met, would be the perfect place to tie the knot.'
While some friends and relatives may possibly be annoyed that they got cheated out of attending a lavish Hollywood wedding, Dolly Parton was not one of them. According to the magazine, she was thrilled.
'I heard she burst into tears and then started singing an acappella version of I Will Always Love You over the phone,' claims an OK! source.
As for the couple themselves, it seems they have zero regrets, with one insider saying of their decision, 'they are very low-key.'