Philly singer-songwriter Mondo Cozmo and his Rolling Stone jacket will grace Firefly on Saturday.

It’ll feel like a homecoming when Philadelphia native Mondo Cozmo makes his Firefly debut Saturday afternoon, gracing The Lawn Stage in The Woodlands of Dover. 

Mondo, who now lives in Los Angeles, said he’s “over the moon” about having his loved ones experience Firefly with him.

“I took up the whole guest list,” he said. “My pops is coming down, my brother and my nephews are coming down. I’m actually flying in the day before to see everybody and hang out with them. I’m really excited.”

The veteran singer-songwriter (whose real name is Josh Ostrander) has been in the music game for more than a decade. He's having a breakthrough year with his fiery single “Shine.” In March, the tune landed him his first appearance on “Jimmy Kimmel Live!”

Have you been to Delaware?

I grew up in Philly, so my pops and I would go down there to buy alcohol.

For those who aren't familiar with your music yet, describe it in 10 words or less.

Good sounds played really loud.

What part of Philly are you from?

I grew up in Bucks County, north of the city. Then I moved down to south Philly when I was just out of high school.

How long have you been in LA?

For about 10 years now. I really like it out here. But most of the time I live in a van, if you know what I mean. The van’s a good place to live too.

In addition to living in a van, what are some of the other sacrifices you’ve had to make to get to where you’re at right now?

I’ve played at every shi**y club. I’ve slept on floors for 15 years. I’ve slept in vans. I’ve made my own t-shirts. I sell my own merch. I write my own songs and record everything in my guest bedroom. You’re looking at a very homegrown thing that took 15 years to get right.

What was it like playing on “Kimmel”?

That was unbelievable. As the guy’s counting down, and his fingers are going down, and it’s five, four … I’m like "how the f**k did I get here?" [Laughs.] I mean, there’s no record out. We’ve only released a couple songs. We’ve only played a couple shows up til that point. And it was just like oh my gosh. I was beside myself.

You looked like you were having the time of your life.

We couldn’t even watch the playback. We had to [immediately] catch a red-eye to Toronto to play with Bastille. We’re watching the playback in the airport on somebody’s iPhone and it hit me: “wow, this is really good.” And then the feedback started coming in from people. It was one of those moments where I didn’t realize it was good until afterwards. It was great.

Who are some of your favorite artists?

I listen to Springsteen as much as I listen to Kanye; I really do. I love the Beastie Boys. I love Dead Kennedys. I love Mariah Carey. I’m just a fan of music. I’m all over the place.

What’s a question you’re not often ask that you wish you were?

I wish they would ask me if I wanted another drink.

Are you homesick? Do you want us to bring you a Philly cheese steak?

Do not bring me that. I’m training for my “Automatic” video. I'm not allowed to have that [laughs].

Talk to us about your Rolling Stone jacket.

Whenever I wear it, it’s like my superhero thing now. It’s crazy. I was at SXSW and Levi’s invited us over to their place. They had this jacket there and I’m like, “that is just awesome.” It was very specific for SXSW. They were like, “I’m sorry but we can’t give that one away. It’s the only one we have.” So [my publicist] Taylor Vaughn hooked it up. I had to do Kimmel a few days later and Taylor was like, “Josh has to wear this. He needs to wear this.” They overnighted it and it’s become this thing. I love it. Now I’m worried somebody’s going to try to steal it - it’s getting to that point. I’m always holding it now if I’m not wearing it.

What’s something a lot of your fans don’t know about you yet?

I’m a huge Philly sports fan.

Where were you when the Phillies last won the World Series?

I was in LA and I cried my eyes out. One time I got to sing the national anthem and I was so thrilled. I said, “My dad is going to be crying his eyes out”. They asked if I could do it and I said, “yes, absolutely.” I called everybody. And then I’m like, “I can’t sing the national anthem.” It’s an impossible song to sing!

You don’t want to embarrass yourself.

Philly will let you know if you’re doing it wrong. They booed Dr. Dog before. They’ve thrown snowballs at Santa Claus. But I figured out how to do it.