“Lil Bub & Friendz,” premiering at this year’s Tribeca Film Festival, is an inside look at the phenomenon of Internet cat obsession. The documentary focuses on fan-favorite Lil Bub, a cat that forever looks like a kitten, and her owner, Mike Bradavsky. The film follows the duo as they travel the country meeting other notable Internet cats.

Lil Bub suffers from the bone disease osteoporosis, but that hasn’t stopped her from going viral with YouTube videos that often garner hundreds of thousands of hits. Co-director and producer Juliette Eisner worked on the film with co-director Andy Capper. Both are employees at the magazine and website Vice, and the two stumbled upon Lil Bub by chance.

“So it kind of all started when I went to the first ever Internet cat festival, which was taking place at the Walker Art Center in Minneapolis,” Eisner said. “At first I was shocked that a really renowned museum was putting on a festival for cat videos, which I thought was hilarious.”

”Essentially I pitched the idea, and we were going to make a very short kind of 10-minute-ish segment for [Vice],” she said. “I actually reached out to Bub’s owner to come along because I thought it would be fun to have a celebrity with us. And after meeting Bub and the owner and getting to know her story, we decided we had to do something longer because it was such an inspiring and interesting story.”

Luckily, Eisner and Capper’s ideas caught the attention of the Internet cat community.

“We started looking into it more and realized that people were just over the moon and obsessed with cats on the Internet, more so than any other animal,” Eisner said. “So we did our research and found A-list celebrities and reached out and told them we were making a movie about Internet cats and Bub to see if they wanted to join, and everyone was on board and loved the idea.”

Among Lil Bub’s “friendz” are Grumpy Cat, Nyan Cat, Keyboard Cat — all celebrity memes — and their respective creators or owners.

And what exactly is it that has propelled our feline friends into such Internet stardom?

“That’s the question of the moment. I don’t know if I have the end all, be all answer to that, but I do think that it has something to do with cats being a little more mysterious than other animals.”

While there is a playful feel to “Lil Bub and Friendz,” the film also carries a real message. Lil Bub has lifted the spirits of many and brought joy — and economic prosperity — to her struggling owner. A small, deformed kitty, perpetually sticking her tongue out at the world, Lil Bub is affecting lives.

A version of this article appeared in the Wednesday, April 17 print edition. Isabel Jones is a staff writer. Email her at [email protected].