Can you sing? Of course you can. In the car you're a rock star but standing in front of a crowd on stage or at a karaoke bar, that's pretty scary. I've found an app that lets you be the rock star you are (deep down) when you're all by yourself, or in front of a worldwide audience.

"Sing" by app developer Smule, is the #1 karaoke app in the iTunes App Store and for good reason. After creating an account (you can sign up with your Facebook account) you'll choose four songs you (think) can rock. The app then displays a catalog of songs in that style. You can also search for your favorite song.

To sing it karaoke style, just tap the song. An instrumental of the song begins to play and the lyrics float up the screen. You can do this as many times and as often as you like for free. If you want to record your performance, you can pay a subscription of $8 a month or a full year for $40. Sing also offers a free 7-day trial.

Here's where this app shines: rather than singing alone you can sing with someone else! Pick a song then choose to sing with one person as a duet or in a group (this is a free feature for all users). As the music begins to play you will see the other person onscreen sing along. The lyrics change color so you know which verse is you and which verse they're singing and when you'll sing together. Once the recording stops, you'll be able to watch your performance. You can also sing a duet with the original artist. Trust me, it's cool.

It's not awkward either because the recordings are made separately and edited together within the app. They'll record their part of the song and you can record yours whenever you choose. Smule posts some of the best duet performances on its YouTube page.

Of course, there are great singers using Sing and many singers who are not-so-good but that's okay. It's good fun.