The former 'Hannah Montana' star is due to wed 'The Hunger Games' actor later this year, but in recent months there has been speculation that they have called off the nuptials, reported the New York Daily News.
Earlier this week, it was reported that the pair were sleeping in separate rooms at the 'Can't Be Tamed' hitmaker's California mansion.
During a shoot in Los Angeles for her new single 'We Can't Stop', the 20-year-old star was seen repeatedly and pointedly displaying a huge ring on the third finger of her left hand.