8 Things You Should Know About Joanna Gaines's Siblings

For starters, Joanna is designing a house for one of her sisters in season 5 of Fixer Upper!

Joanna Gaines is welcoming someone super special to : her little sister, Mary Kay McCall!

took to Instagram to post that her sister is moving back to their hometown and into a home designed by Joanna herself.

"Today's house was my all time favorite ," Joanna wrote in the post. "We got to reveal this house to my sweet sis and her family of seven (going on 8!). I can't contain the excitement-after nine years they are finally coming back to Waco! Can't wait for you to see this episode 😍 ."

Joanna hinted that her sister would be on an upcoming episode when she posted a picture of their design meeting back in June.

Now that's she's back in Waco, we can only hope to see more of Mary Kay on the show and learn more about . Here's what we know about her sisters so far:

1. There's three of them.

Joanna has an older sister, Teresa Criswell and her younger sister, Mary Kay — and they all definitely look related.

2. Mary Kay has the best nickname.

Mary Kay is affectionately called "Mikey" in Joanna's social media posts.

3. They all love plants.

These #plantladies can be seen grabbing greens from both Joanna's garden and Magnolia Market. We're expecting plenty in Mary Kay's Fixer Upper reveal!

4. They're just as silly.

When they get together, these sisters are known to goof off, just like their kids. (It looks like they had a rad too much candy at the Sugar Factory in New York City!)

5. They're super supportive.

Even with all of Joanna's success from the show, there's nothing but love between these sisters.

6. Big families are a must.

Even though Joanna's family of six is considered large, her sister Mary Kay has her beat and is expecting her sixth child soon.

7. Teresa runs a show of her own.

Older sister Teresa hosts an inspirational YouTube show called . She also writes lifestyle and faith-based posts at her blog , and posts about healthy mother-daughter relationships on

8. They were the cutest little girls.

Teresa frequently posts photos of the three of them as children on Instagram and they were absolutely adorable!

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