"The Little Couple" stars Dr. Jennifer Arnold and Bill Klein like to be honest with their children Will, 3, and Zoey, 2.
Interested in ?Add as an interest to stay up to date on the latest news, video, and analysis from ABC News.
As a way to explain what a physician does, Arnold, 39, went into some detail with the children in a sneak peak video before her daughter Zoey was to go for a checkup the next day, People magazine revealed.
The clip -- filmed earlier but set to air tonight -- shows Will, who picks up the stethoscope and immediately started checking up on his mommy, saying "sick."
The reality stars revealed Arnold's cancer treatment late December. She was diagnosed with stage 3 choriocarcinoma, a rare cancer that formed during a non-viable pregnancy she had in September.
"Will understands that mommy's sick, and it's touching, we don't hide anything in our house," Arnold says in the clip.
In February, Arnold revealed that her cancer was in remission.
"It's official- ME 1 vs CANCER 0... I WIN! Thank you for all the prayers, thoughts, & support!" she tweeted.