'Where is she hiding him!' Fans can't believe this model is eight months pregnant

A heavily pregnant 33-year-old model only has four weeks to go before she gives birth, but fans can't stop commenting on her petite baby bump.

Sarah Stage, a lingerie model and already a mum of one, stunned her 2.3 million Instagram followers by sharing photos of herself in the later stages of pregnancy, with some commenting on how compact her tummy appears.

'Stay patient and enjoy your journey! ❤️🤰🏻👶🏻(one of my fav quotes at the moment ☺️) #9monthspregnant' Sarah wrote in the caption of one of the pics, followed by another which she simply updated as: '#36weeks 👶🏻'

Many fans couldn't contain their shock at the size of her bump, with one posting: '9 months 😱 pregnant!' whilst another added: '36 weeks 🤣🤣🤣'

One fan wrote: 'where the hell is she hiding him!', followed by a second who exclaimed: 'how THE FUDGE is she 36 weeks pregnant 😂😂 I look like this after a bowl of pasta'.

'ARE U EVEN REAL 😩😩😩 #goddess', posted another fan.

Exercise is a big part of the Instagram model's life and as such she has continued her regime throughout pregnancy - even sharing short videos to show how she's working it into her days.

Sarah captioned one post with: 'Ahhhh!! This week I'll be #9monthspregnant 👶🏻 I've still decided to continue exercising 2x a week which has kept my energy level up (not as energized as [her son] James tho 😂)'.

The expectant mum, who continues to baffle people online with her six-pack abs, also shared her weight gain so far, writing: 'Total weight gain so far: 18lbs,' and in an earlier Instagram post admitted she had been 'craving a Salted Caramel Chocolate Peanut butter Banana smoothie.'

The mum-to be explained: 'A lot of you keep asking how much longer I plan on working out this pregnancy and the truth is until I feel too tired/uncomfortable or when my doctor advises me to stop!'

Sarah and her husband Kris told the Daily Mail that this baby will be their last. The couple are already parents to two-year-old son James Hunter, who is 'patiently waiting doe his baby brother'.

'In the meantime I'm trying to spend as much quality time with Jamesy while also preparing him to be a great big brother 👨👩👦👦' Sarah added.