However, after seeing her latest post on Twitter, could the singer have gone too far with her exercise routine?
In the photo Miley is seen showing her off her mid-drift in front of mirror wearing her fiancé's joggers.
Alongside the photo, the star tweeted: "my "Fiancé" jeans. but for real though".
Miley's figure has shurnk over the past few months as a result of vigorous workouts.
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Despite growing concerns that Miley has lost too much weight, her personal trainer Mari Windsor has defended her saying that 'people need to chill out'.
Mari stated: 'She's healthy and she feels good, that's the main thing. She's smart about her body. She wanted to sculpt her body, that's all.'
Back in April, after the star had visibly begun to lose weight, Miley was forced to defend herself, explaining that her weight loss was down to allergies.
Miley told her critics: "For everyone calling me anorexic, I have a gluten and lactose allergy."
The singer became engaged to 'The Hunger Games' actor Liam Hemsworth in May this year after the two worked together on film 'The Last Kiss'.
The couple are said to blissfully happy together.
Well, as long as Miley is happy and healthy then that's all that matters to us.