Former Scrubs star Sarah Chalke will guest star on an upcoming episode of Grey's Anatomy and play a role that required her to cry a lot, some of which she could not control because of the storyline's personal connection to her real life.

Two years ago, Chalke and her fiance Jamie Afifi found out that their son Charlie, then barely 12 months, was diagnosed with Kawasaki Disease, a rare ailment that was hard to diagnose and needs to be treated quickly, according to TV Guide. The disease inflames blood vessels throughout the body and there is approximately a 10-day window to get effective treatment before it is too difficult to treat.

"You present with all these symptoms, you get a lot of repeated misdiagnoses, you keep getting sent home [by doctors]...," the actress shared. "We had a really hard time getting him diagnosed."

Chalke spoke about the ordeal at the Save a Child's Heart fundraiser in November of 2012 and to further raise awareness about the rare disease, she met with Grey's creator Shonda Rhimes and executive producer Betsy Beers. It was decided that Chalke would star in the March 28 episode of Grey's as a single mother who arrives at Seattle Grace hospital with her infant son after suffering repeated misdiagnoses yet having a feeling that something is wrong.

The disease is not only internal: it can be spotted with abnormally, bright red lips, red eyes, body rashes, skin peeling on the fingers, and a lingering fever, the report added.

The episode is titled Can't Fight This Feeling.

"Oh my God... There were some tears," Chalke said about filming the episode. "As an actor, you're usually like, 'Will I be able to cry when I'm supposed to cry?' But this is more like, 'Will I be able to stop crying when I have to stop crying?' "

She added that taping a storyline connected so closely to her everyday life "was definitely a bit scary to tackle," adding the following:

"I didn't know what that experience was going to be like, to hold a baby who was made up to look like Charlie did at the time. It was probably the most challenging thing I've done...The thing that means so much to me...is raising awareness about [KD], so that it doesn't go untreated [for other families]."

Grey's Anatomy airs Thursday nights on ABC at 9/8 p.m. Central.

Episode 17 of Grey's Anatomy, part of its ninth season, airs Thursday, March 14, at 9 p.m. ET on ABC. Watch its promo video below.