On Monday night (August 17), "The Walking Dead" star Norman Reedus posted a photo on his Instagram account that seemed to have a little bit more of a story behind it than just his normal selfie with Steven Yeun, or snap of his chubby cat. The photo -- of a photo -- is of a girl in a red dress, holding a flower. "To Norman. Love, Ava," it reads.

Ava looks beautiful and serene, but maybe also just a little bit tough in the picture -- a toughness that probably comes about out of necessity, as she is completely bald. "Ava ❤️," Norman captioned the pic.

Now of course, Norman paying attention to a devoted fan isn't exactly new -- it's what's made him such a popular figure at conventions, after all, and "If Daryl Dies, We Riot" didn't come to be because fans don't love him. But when MTV News tracked down and contacted Ava's mother to ask about the picture, we quickly learned that there's a whole lot more to Reedus and Ava's story than just a simple Instagram photo.

"She has alopecia areata, and that started back in September of 2013," Ava's mother, Heather Truesdale, told us over the phone. "She started losing her hair. Three months later, and her hair was completely gone."

During this difficult time, Ava became attached to "The Walking Dead" -- Heather and her husband pre-screened the episodes she watched for content, and Ava fell for Daryl because "he's a loyal friend" -- so Heather decided to take Ava to see the cast during a long, 12-hour day of filming in a nearby Atlanta suburb. Ava gave Norman a photo she had drawn of Daryl, and a friendship was born.

"He was so sweet to her," Truesdsale continued. "He called her ‘sweetie’ and ‘cutie,’ and he really liked her picture."

A few months later, Ava and Heather ran into Norman again at the Walker Stalker convention in Atlanta -- and Norman being Norman, he "just stopped what he was doing, came around the table, grabbed her, took her, and walked the convention floor with her, shooting silly string at the other actors and fans." He later returned Ava to Heather and apologized for "stealing" her daughter, but he clearly wasn't that sorry, because he did the same exact thing later on that same weekend.

... Which is great and all, but the real kicker came the following Christmas, when Heather created a mommy-run Twitter page for Ava, to share all of the photos she'd taken of the two of them with interested fans. Norman noticed Ava's Twitter page, followed her, sent her a direct message, then gave her a shout-out to his millions of followers.

"It was very difficult for her to have to go to school as a 7-year-old girl, bald," Truesdale explained. "She thought it was so cool that his handle was 'bigbaldhead,' because I was like, ‘you’re his little bald head!’ She just thought that was the coolest thing ever... and she’s seen some of Norman’s artwork, and his photography, and I’ve explained to her, ‘See, there’s beauty in things that are not just obvious beauty. Even though you’re going through this, it’s just hair -- it’s not something that’s physically harming you. Even though this does suck, it’s just hair. We can fix that, and it’s not going to stop you from anything else.’"

Months later, Ava and Heather decided to pay "The Walking Dead" set another visit -- Ava, now nine, was enjoying the fact that her hair was growing back thicker, and wanted to show off her little, not-so-bald head without her token bandana (and of course, she also had drawings, silly string, candy, and treats for Norman's cat that she needed to give to him).

Norman enthusiastically accepted the gifts and gave out hugs, but in the chaos of greeting other fans, Ava's school picture ended up flat on the floor. Norman had already left by the time Heather and Ava picked it up, and a kindly member of the "Walking Dead" crew promised to give it to him... though of course, Heather didn't have very high hopes that this would actually happen. So just imagine her surprise when, two months later, Norman revealed to 2.6 million Instagram followers that not only did he get the photo, he kept it in his trailer.

"I was misty eyed, she was screaming and cheering, and it just made her day," Heather said, with Ava herself adding that she was "in total shock."

And of course, Heather notes that the comments on Norman's post, which call Ava "beautiful," mean a whole lot to a kid who looks different from all of her friends with long hair.

"We don’t want her to be superficial, but it definitely does boost her confidence when she’s got one of the biggest stars in the world posting a picture of her with a heart next to her name," Heather said.

After chatting with Heather and Ava over the phone, it's clear that Ava -- who is a second-degree black belt, a straight-A student, and a dedicated horseback rider -- doesn't actually need celebrity attention to keep being a little asskicker, despite the setbacks that have come with the alopecia. But of course, it doesn't hurt!

"He’s very loyal, he’s smart, he makes me more confident, he makes me feel stronger," Ava said. "And he’s funny. And he gives the best hugs."

To learn how you can help kids like Ava, visit Childrens Alopecia Project and the National Alopecia Areata Foundation.