Bruno Mars is already sitting atop the Billboard Hot 100 with alternative hip-hop artist B.o.B's "Nothin' on You," and he's a part of Travie McCoy's "Billionaire" — also a Top-20 hit.

Today, the rising collaborator/producer — who performed as "Little Elvis" as a youngster and graduated from Roosevelt High School in 2003 as Peter Rodriguez — officially steps out as a solo artist as his four-song EP collection, "It's Better If You Don't Understand," is released on iTunes.

"I don't know if people know what to expect from me as a solo artist, but I'm hoping these four songs will give people a taste of what I'm about and make them hungry for my album when it comes out later this year," Mars said. "These are all fresh songs. We just finished them a week ago. We haven't had time to put videos together. I want to see which song people will gravitate toward."

At 23, Mars is one of the most grounded and fastest rising stars you'll find. He moved to Los Angeles, after graduating from Roosevelt at age 17, and he has built a foundation in the music industry as part of the songwriting/production team Smeezingtons (with Phillip Lawrence). While he has spent the better part of seven years writing and producing for other artists, the general public has gotten to know Mars recently as the up-and-comer on B.o.B's No. 1 single "Nothin' on You." On the track, Mars sings the catchy "beautiful girls, all over the world, I could be chasing but my time would be wasting, they got nothing on you." His sweet sound has not only vaulted him into the world spotlight, it's also raised expectations and anticipation for today's solo debut.

All four tracks were bootlegged and put on the Internet last week, Mars said, along with about 30 other numbers he had been working on.

"Our record company's computer was hacked," Mars said. "That's technology for you. It's disappointing because you work so hard for so long and then someone sets it out there for you to grab for free before it is ready for release. There are some other songs I was just playing with and they're like: 'Here's Bruno singing about guys.' It's crazy — and I'm not gonna put guys or boys in a song again," he said, laughing.

"It's Better If You Don't Understand" is a mix of catchy tunes that are kind of a cross between between Jason Mraz and the Plain White T's. Very smooth, easy to listen to, with a good beat.

Mars' take on each track:

"Talking to the Moon" — "I wrote it for myself. It's a heartbreak song coming from a deep and dark place, but I'm coming at it in a different way. Instead of 'I love you, please come back,' I sing about going crazy without you and hope you are, too. This is one I wanted to sing the way I wanted to sing it."

"Count on Me" — "What's funny about this is that it's probably the fastest song we've ever written and I think it may be the most catchy. It took just 30 minutes. I jumped on the guitar and just started playing three chords, freestyling almost. I feel like it's the song that got me signed and I didn't realize how deep it is until after we finished. 'Count on me like 1-2-3' sounds simple, but I'd never heard it before. We just wrote it. What's great about it is that not at any point do I say 'baby,' or 'girl.' It's about telling someone you have their back at all times. Anyone can relate to it."

"Somewhere in Brooklyn" — "My father is from Brooklyn, and now that I do the music thing, I travel to New York a lot. It's a magical place everyone can relate to, the city that never sleeps. It's about a girl I lost in Brooklyn. Took me about a month to finish."

"The Other Side" — It's a funky song and I got to work with Cee-Lo from Gnarls Barkley on it. I've been a big fan of his. I love the way he performs and sings. He came in and sang the crap out of it, and I got B.o.B. on this song, too. It's really an interesting song. It's us telling how we live our lives on the other side, almost vampirish. It's just how we feel."