Hot new app helps aspiring musicians be their own Justin Bieber

The path to pop stardom has just taken a surprise turn — and it goes through your iPhone.

A new, free mobile app called “Acapella” allows aspiring Adeles, Lil Waynes and Rihannas not only to shoot videos of themselves singing songs, but also back themselves up by layering in multipart harmonies, rhythm tracks and musical instruments.

“Where are you now that I need you?” a geeky-looking teen in glasses croons, channeling Justin Bieber in two-part harmony inside a pair of adjacent panels that he recorded, one by one.

Meanwhile, the would-be Beeb keeps rhythm with a ballpoint pen, toilet lid, a box of Minute Rice and his head banging on a desk — across five panels arranged below.

“This is the beauty of Acapella — it gives you a chance to showcase your skills,” says Daniel Vinh, who with cofounder Ihung Tu launched the app less than two months ago.

Since then, the app has seen more than 6 million downloads, having topped the free charts in Apple’s App Store for 10 days straight before recently settling back to the top 30.

Viral Acapella videos are scoring millions of views after getting posted on Twitter. In one hilarious clip that has been retweeted more than 10,000 times, a teenage girl recreates Shaggy’s “It Wasn’t Me” in five parts, pulling faces as she acts out dialogue and lays down beats.

Many clips are impressive, and look like they were made by professional singers, guitar players or classical violinists taking a break.

Still, while other apps like Four Track have catered to musical talent, Acapella’s designers wanted to make an app anybody can use.

“I thought it was going to be easy to do it,” says Tu, noting that a key challenge is making sure audio tracks sync perfectly when they’re being layered in.

“I thought if your audio’s off by one 100th of a second it wouldn’t be noticeable,” Tu said. “I was wrong — it’s more like one 10,000th of a second.”

With everything clicking (including a built-in metronome), Acapella — part of Tu and Vinh’s larger mobile photo —  and video-production platform called Mixcord — now has more than 10 million monthly active users (MAU).

“The growth potential is huge — we can absolutely reach 1 billion MAUs,” Vinh predicts.

While Acapella’s free version imposes a one-minute limit on compositions, users can buy the ability to compose opuses of three and 10 minutes for $1.99 and $9.99, respectively.

Still, 95 percent of Acapella compositions are under 60 seconds, the app’s creators say.

Mixcord’s other apps include Picplaypost, a video-collage app; and Square video, which right-sizes rectangular video footage to fit an Instagram frame.

Mixcord has raised $1 million in seed funding led by Los Angeles-based Mucker Capital.