A New York surgeon spotted a woman's thyroid tumour from his couch when he saw her shopping for a home on HGTV.
Nicole McGuinness, 32, was featured with her father on the show Beachfront Bargain Hunt.
They were celebrating the conclusion of Nicole's two years of treatment for the rare and extremely aggressive brain cancer that Senator John McCain is battling, according to the Daily Mail.
But, in his own home, Dr Erich Voigt identified a worrisome mass on Nicole's neck, and posted to Facebook that she might have another tumour to battle yet.
Through the social media network, Dr Voigt eventually found Nicole, and urged her to get an exam and biopsy of the mass.
His reality HGTV indulgence may have saved Nicole's life: she went to a specialist in her home state of North Carolina and was diagnosed with thyroid cancer.
In her HGTV segment, Nicole is bright-eyed and grinning as she and her father hunt for their dream beachfront home.
On the show he looks far healthier than she does in a photo the segment zooms in on from during her brain cancer battle, in which a large, maroon blotch covers the upper left quadrant of her face.
Nicole had been diagnosed with a stage IV glioblastoma - the same cancer the Senator John McCain is currently battling - in 2015, before she was 30 years old.
Typically, this aggressive cancer does not strike people before they reach their 60s.
She was lucky and survived the cancer, which has just a 30 percent two-year survival rate, completing her treatment last summer, which can include radiation, chemo and even brain surgery.
With a new lease on life, she wanted a new home of her own, and Beachfront Bargain Hunt was the perfect opportunity to find one.
But neither her chipper attitude nor the professional make up done for her by the HGTV crew could distract Dr Voigt's sharp eye.
As Nicole spoke, he could see a lump about the size of a strawberry nodding up and down at the front of her neck.
With nearly 20 years of experience as an ear nose and throat doctor and surgeon at New York University Langone Health, Dr Voigt immediately recognised the worrisome spot.
"As a head and neck surgeon, I'm trained to notice these things," he told ABC News.
He wanted to warn this stranger, so he took to Facebook.
On his own page, he wrote: "I am watching a TV show and notice this woman has a left thyroid mass. She needs a sonogram and fine needle biopsy I wonder if she knows and hope it's benign."
Through the social media grapevine, Dr Voigt's message reached Nicole just days later.
Nicole herself is not on Facebook, but a friend of her mother relayed the message.
"We were sort of in shock, we did not expect a doctor, on television, from states away that we did not know to come up with some kind of diagnosis," Nicole told Good Morning America.
But, a cancer veteran, Nicole wasted no time and went straight to a specialist.
Dr Voigt's fears were confirmed: Nicole had thyroid cancer.
Women are about three more times to get these kinds of cancers and about 56,000 new cases are diagnosed each year.
Signs of the disease include swelling, changes to one's voice and lumps like the one that Dr Voigt noticed on Nicole's throat.
"It's just a miracle, in my opinion, that he happened to see this on television," Nicole said.
Remarkably, Dr Voigt is not the first to diagnose someone he saw on TV. In fact, he isn't even the first to diagnose someone on an HGTV show with a thyroid tumour.
In 2013, Tarek El Moussa, star of the network's show Flip Or Flop was diagnosed with thyroid cancer after a nurse spotted a lump in almost the same spot on his neck.
On Monday, Nicole met Dr Voigt for the first time on Good Morning America.
"I'm going to try to say this without getting emotional. I have gone through a lot these last couple of years and never expected to have to be a cancer survivor twice, but without you keeping a vigilant eye and watching that television show, who knows how long I would have gone on without that being checked.
"So, from the bottom of my heart, thank you," Nicole told Dr Voigt.
Nicole credits her optimism for her survival through her glioblastoma battle, and says she will do the same this time around, staying positive and fighting.
Thyroid tumours are rarely cancerous, like hers, but even when they are, 98 percent are curable.
She said that she has an excellent and trusted oncology team at Duke University - plus, Dr Voigt "by [her] side."
Later this week, Nicole will meet with her doctors for a check-up and to discuss the best course of treatment, which may include radiation, chemotherapy and perhaps surgery.