By Mai Martinez

ELMHURST, Ill. (CBS) — Keenan Cahill says he always wanted to be an actor or singer and started lip-syncing in his room and posting the videos online as a way to “put himself out there.”

But As CBS 2’s Mai Martinez reports, Cahill never imagined the fame he’d find online.

At York Community High School, he’s just another sophomore, but online he’s larger than life, performing with some of the biggest names in music, from 50 Cent to David Guetta.

So how did this all happen to the 16-year-old from Elmhurst? The answer: a little time, a big dream, and a computer, all from the comfort of his own bedroom.

“At first it was just like, ‘Make a YouTube channel just for fun just to see what would happen,’” Cahill says.

What happened was not much, until Keenan recorded a lip-synched version of Katy Perry’s “Teenage Dream.”

The singer heard about it and tweeted “I heart you @KeenanCahill” and “THIS…is my Teenage Dream,” with a link to Keenan’s video. It went viral, making Keenan an instant Internet sensation.

Why did people react that way?

“I have no idea. I don’t find it funny at all,” Keenan says.

But millions do, including countless celebrities who are eager to co-star with Keenan. From singers to athletes, and even models, some popping by his house.

“Just Thursday night I’ve got Tyra Banks knocking on my door and going upstairs and doing a video with Keenan,” Keenan’s mother, Erin O’Brien Cahill, says.

During such encounters with celebrities, she says, “I hope my house is clean enough.”

Erin says she welcomes any distractions that take her son’s mind off the reality of  MPS-6, the life-threatening disease that has stunted her son’s growth.

“The focus is not on the disease anymore, but it’s on more positive things in his life,” she says.

As for Keenan, he couldn’t be happier because his teenage dream is now “basically a dream come true.”

So what’s next for Keenan? He wants to actually sing now and hopes to release his first single later this year.

After working with so many artists, Kennan said his dream co-star would be Chris Brown.

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