A 91-year-old grandma has attained social media stardom as half of a comedy duo alongside her 25-year-old grandson.

Five years ago, Ross Smith was in college at the University of Dayton when he started filming six-second videos on Vine. He had amassed a sizable following, but for one of his clips, he asked his grandma Pauline “Granny” Kana to block one of his basketball shots. And from there everything skyrocketed.

“My brand just turned into me and Granny taking over the world,” Smith said.

Today, Ross and Granny have 15 million followers on social media, including more than 4.6 million followers on Facebook and 2.1 million Instagram followers on Smith’s official accounts alone. The two beat out more than 17,900 videos to win $100,000 through viral media website 9GAG’s “Fun Off” contest, with almost 250,000 likes. The combo do everything from trick beer pong shots to trying out flamethrowers to making parody videos for rap songs.

“Our humor is universal,” Smith said. “Everyone knows Granny is funny.”

For the first three to four years, the clips were viral but not exactly profitable. Smith took some time off from his social accounts to pursue an MBA at the University of Dayton and play pro football in Europe in 2015. But he realized he enjoyed working with his grandmother, so he started pursuing it full time and was able to parlay it into a successful career for the both of them.

Part of the show’s appeal lies in their genuine relationship, said Russell Schneider, 9GAG’s head of sales and business development.

“Ross is like a young man next door,” Schneider said. “It’s very rare for us to see a grandmother and grandson grow close and have fun with each other like BFFs. It’s this cross-generational BFF relationship that makes them so special.”

Granny said there’s a misconception elderly people don’t like or use social media. She uses Facebook to keep in touch with family, and enjoys watching viral dog videos.

“Some of the elderly love it,” Granny said of Facebook. “It’s interesting. You see different parts of the space, the world and the people all around having a good time. Seeing people doing things, I like it!”

Granny gets the idea that their act is a big hit – though she calls every platform Facebook, Smith noted. However, she didn’t really realize how big of a following the two of them had the first four years until Smith got her an iPad for Christmas. After that, he couldn’t hide their videos from her.

“Even when I’m walking to the plaza, which I live about three blocks away, sometimes people going by with their cars they stop and say, ‘You’re Granny!'” Granny said. “When I get to the plaza, the people in the stores they come up to me. It’s just a party at times.”

Her favorite video she’s done involves her raking a pile of leaves over a secret saucy message written in chalk on concrete. Or, it’s the time she got to film with her celebrity crush Chuck Norris — she appreciated his sincerity and generosity toward everyone who was filming with them.

“First time Chuck has been beaten in his whole life,” Granny boasted.

Most important, she enjoys being around her grandson and learning about him throughout the process.

“He’s easygoing, happy-go-lucky,” she said. “He likes to try everything, and everything just seems to fall in place.”

Smith is amazed by how much their act has taken off and that he could make a career out of hanging out with his grandma. The two are continuing to work on their social media videos and have a television show in development. They’re also working on raising money for Alzheimer’s research. By the end of this year, Granny hopes she’ll be able to learn how to drive for the first time. (She failed driver’s training in her youth.)

Most importantly, Smith has learned his grandmother can still teach him quite a bit. She won’t throw away milk when they go on vacation, Smith explained. She’ll put it in the freezer for three weeks because she grew up poor and “back in the day that was precious food and drink.” It’s taught him to value material things more.

“Honestly most people – and I was probably one of those people at the time – don’t have respect for the elderly,” Smith explained. “Once you’re old, you kind of go away and go to a nursing home. Doing this opened my mind to how awesome old people are and how cool they live their lives. They appreciate the small things we don’t appreciate in this fast-paced advertising industry-based life.”