On the eve of their debut album release, Alex & Sierra have shared the music video for their next single titled 'Little Do You Know.' The track appears on their album 'It's About Us' which will be released tomorrow, Oct. 7.

'Little Do You Know' was co-written by Toby Gad, who has also penned such hits as Fergie's 'Big Girls Don't Cry' and Beyonce's 'If I Were a Boy.'

In this emotional video, the musical duo (who are dating in real life) play a love torn couple going through a difficult phase in their relationship, although still know that there is love underneath the pain they feel. The two seemingly can't stop thinking of one another as they separately wander through the streets during a sleepless night before meeting each other at dawn.

Sierra sings, "I've been holding back for the fear that you might change your mind / I'm ready to forgive you but forgetting is a harder fight / Little do you know / I need a little more time."

Click on the video above to watch the music video for 'Little Do You Know.'