Sarah Stage
Model Sarah Stage attends the 2016 MAXIM Hot 100 Party at the Hollywood Palladium on July 30, 2016 in Los Angeles, California. Getty

Dubbed the 'Six pack mom', Sarah Stage perplexed fans throughout her pregnancy with a barely-there bump – and jaws continue to drop after the fitness model showed off her incredible recovery from labour.

The 36-year-old shared was captured wearing a pair of skinny jeans as she left the hospital with her husband Kris Jason and their other son James on Thursday (10 October). She welcomed her little boy, who weighed 7pounds 2oz, just 72 hours earlier.

"Headed home with Baby Logan! We can't stop smiling! #teamNoSleep #parentlife," she captioned the picture, which showed her seated in a wheelchair with curled hair and ripped blue high-waisted jeans. She was flanked by her husband, who was pushing the chair.

Scores of her flabbergasted 2.3 million followers couldn't believe their eyes and took to the comment section to express their shock and admiration in equal measure.

"You look incredible!" one said of her perfectly preened appearance. "I couldn't fit into my jeans until months after I delivered. I also came home from the hospital looking like crap, hair in a bun, no make up and pjs."

Another said: "Looks like you just came home from a checkup for baby Logan not for giving birth! This is Amazing God Bless you, you're truly giving me inspiration."

A third asked her to share some tips on what helped her during labour and delivering, before adding: "Also I can't believe you are in jeans! I feel like when it's my turn I will be in a big old grandma mumu[sic] Hard to believe you just had a baby, you're glowing! congrats!"

Stage's second child arrived via C-section on Monday. "We are so overjoyed and happy to welcome baby Logan into our family," the couple said in a statement released to E News!