As he told an audience at a gala dinner shortly after their engagement in May 2012: "We read together, fell in love and now we're getting married."
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Sadly, the wedding never happened and after three tumultuous years the couple have stopped playing the on-off game. The Wrecking Ball singer's 3.5-carat Neil Lane engagement ring is firmly off her finger for good and she's nursing an achy breaky heart.
During the course of the romance so much has happened to the charismatic young couple. She's shed her locks and her Disney image, growing up before our eyes into a latter day Lady Gaga or Madonna.
Meanwhile, her laid back Australian beau has gone on to worldwide fame in The Hunger Games.
Here, we look back at the most touching moments in their romance.