'This Time Next Year' is a UK-based reality show that turns the standard reality makeover program on its head. Its premise is simple: it challenges everyday people to bring about a massive change to their life - whether it's losing weight, starting a family, or overcoming an obstacle like an illness or a medical condition.

Last year, Fiona Walker, a school teacher from Salford, vowed to lose eight stone (over 100 pounds) so that she would be eligible to begin fertility treatment and start the family that she had always dreamed of.

"Doctors told me they can't do anything else for me until my BMI hits 30," she said last year, ahead of her transformation. "Currently it is 48, but it would mean everything to me. Having a baby is the last piece of the jigsaw, I've achieved everything else in my career and love life."

Walker also revealed that she suffered from polycystic ovary syndrome (PCOS), a condition that can also make it difficult to conceive. She admitted that she struggled to lose weight in the past and even became a 'yo-yo dieter', without any lasting success. As part of her pledge to not only become healthier for herself, she also vowed to remember another reason why she was doing this: so that she could become a mum.

On this Tuesday's show, Walker's incredible weight loss transformation was revealed. Stunning the audience with her new look, she joined host Davina McCall to share that she lost an amazing 80 pounds (just 20 pounds shy of her goal).

But she also had some incredible - but heartbreaking - news.

"A few months ago I actually fell pregnant naturally," she said. "Unfortunately, I lost the baby, [but] the weight loss has kickstarted my body, and it did it naturally."

Fans on Twitter immediately responded with an outpouring of love and support for Walker. In a surprising twist to an already emotional story, Walker also took to Twitter following the episode to reveal yet another surprise.

"So surreal seeing myself on TV!" she began. "Thank you so, so much to the show for giving me the incentive I needed."

But there was more.

"I can now say I am currently 22 weeks pregnant with a baby boy!" she tweeted.

Congratulations Fiona!

'This Time Next Year' also airs in the US on the Lifetime network.

NEXT: 21 Things That Can Help Women With PCOS Get Pregnant