Even Beyonce has to rehearse before performing live, especially when it's in front of a huge television audience. Before taking the stage to premiere the song on 'American Idol' on Wednesday, the 'Single Ladies' superstar was caught on tape (by hubby Jay-Z!) belting an a capella rendition of her new ballad, '1+1.'

"Sometimes you need perspective. You’ve been right in front of greatness so often that you need to step back and see it again for the first time. This is the dressing room rehearsal for American Idol. NO MICROPHONE. No effects," Jay-Z posted in his Life + Times blog, including a hidden video of his wife singing in the dressing room.

Not that we needed this behind-the-scenes clip to tell us, but Beyonce has mad talent -- and it's only amplified when she's stripped of her back-up music, mic, and booty-shakin' moves. Here, the Texas icon shakes the room with her big voice, and is accompanied by only a keyboardist (and, when it's their turn, a few back-up singers). We see why Jay-Z is so proud!

Watch Beyonce Rehearse '1+1' Backstage at 'American Idol'