LOS ANGELES (Reuters) - Justin Bieber is stripping down. Musically, that is.

The Canadian pop phenomenon showcases his vocal and song-writing talents with a new acoustic album, out on Tuesday, that also features three new tracks including a heartbreak ballad thought to be about his former girlfriend Selena Gomez.

"Believe Acoustic" sees Bieber, 18, change up the arrangements of songs from his fourth chart-topping album "Believe," released last June, singing with only a guitar or piano-driven melody.

Uptempo songs such as "Boyfriend," and "Beauty and the Beat," which roped in electronic sounds with fast-paced dance beats, are slowed down as the singer uses his vocals to manipulate the vibe of the song.

"Believe Acoustic" sees Bieber return to his acoustic roots five years after he was discovered on YouTube, singing on the streets of Canada accompanied only by a guitar.

It was released following Bieber's failure to pick up a single Grammy nomination this year, despite having a chart-topping album and a sold-out world tour.

Bieber often performs acoustic versions of his hits, most recently at the American Music Awards in November, where he delivered a stripped-down version of dance song "As Long As You Love Me."

The teen singer released "My Worlds Acoustic," in 2010, featuring alternative versions of tracks from his debut studio record "My World."

But most ears now are turned to new track "Nothing Like Us", which follows Bieber's widely reported split from former Disney Channel star Gomez.

It features Bieber singing a raw and emotion-filled ballad over a piano melody, with lyrics such as "Girl, why would you push me away?/Lost in confusion, like an illusion...But that is the past now, we didn't last now."

SIMPLE LOVE SONGS

Bill Werde, editorial director of Billboard music magazine, who interviewed Bieber a few months ago, said the song was "directly about Selena" and that fans were anticipating the singer sharing "his feelings about something this personal."

The new track is not dissimilar to the heart-break odes written by country-pop darling Taylor Swift or British soul-pop singer Adele.

Werde said he hoped people would take notice of Bieber's song-writing and vocal production skills on the new album.

"Some of the best songwriters that are working out of our pop space are the ones that can take these very, very specific feelings that you would expect a teenager or a young adult to have and then sing and write about them in a way that makes them universal," Werde told Reuters.

"That's a skill that needs to be respected. It's not easy to write great, simple love songs."

The other new songs are "I Would," a sweet love song, and "Yellow Raincoat," a mellow survival song with the singer crooning softly "cause the fame and the money and the girl will drive you crazy...I'm thinking maybe just put on my raincoat."

Bieber may not be winning Grammys just yet, but the singer could make chart history if "Believe Acoustic" reaches No. 1 in the Billboard 200 album chart next week.

The singer will become the youngest artist to have five No. 1 albums under his belt, and one of few artists, including The Beatles and Jay-Z, to have a No. 1 album each year for four consecutive years.

Bieber, who surpassed Lady Gaga earlier this month to become Twitter's most-followed person, will make his television hosting debut on "Saturday Night Live" on February 9, the night before the Grammy awards.

Bieber told Billboard he would not be attending the Grammy awards ceremony in Los Angeles.