Monica joined Ruth Langsford and Eamonn Holmes on This Morning to show off her new slimmer figure, and revealed that she's lost a whopping five stone.
She spoke out about her decision to get a gastric band fitted after feeling unfit and unwell on tour with Blue.
'I was always battling with my weight. It was always a demon of mine that I had to battle.
'In 2015 I was on tour with Blue and I could feel how unfit I felt. I remember coming off stage and crying my eyes out.
Left: Monica pictured in November 2015. Right: during her appearance on This Morning
'I felt unhealthy and out of breath. I was eating excessively or fad diets where I would put on double the amount of weight that I'd lost.'
At her heaviest, Monica weighed 15 stone, and says she doesn't regret taking 'drastic action.'
'It's the best thing I've ever done' she told the presenters and the audience. 'Food was my addiction and I couldn't control it.'
Ruth and Eamonn joked about people cheating while having a gastric band, and eating whatever they want. However, Monica revealed that she's been very strict with her diet to get to where she is now.
'I did something so drastic. I need to learn to respect it now. With a gastric band you need to respect it. I've cut out bread and a lot of carbs,' she said, before revealing that her typical breakfast is eggs, salmon and avocado.
Monica also said that she started to notice changes 'within the first two weeks' of the band being fitted, and that she wants to have 'a little bit' of the band taken out so that she can eat more once she starts weight training.
The star explained that lots of her workouts have been cardio-based, but she now wants to tone up!
Fans and viewers were quick to offer their opinion on Monica's new look on Twitter.
'Wow Monica on #ThisMorning amazing achievement @ThisMorningShow #determination' wrote one Twitter user. However, not everyone was pleased with the fact she used a gastric band to get her results.
'Getting a gastric band and saying you've lost weight is like getting hair extensions and saying your hair has grew #thismorning' wrote another.
Would you ever consider a gastric band to lose weight? Let us know in the comments below