"Us Against The World" is the first single by R&B and pop singer-songwriter and actress, Christina Milian, from her fourth studio album, which is set to be released in Spring 2009. The song was written by herself, she described it as a "cinematic power ballad". Milian calls the song a love anthem because she wrote it while watching a Romeo and Juliet film. Milian finds it to be more dramatic than her other singles, and explains it is about "having somebody to be there for you through thick and thin".

Milian believes the lyrics speak a million words for people all over the world: "It's about passion, true love and sticking by someone through thick and thin. Life and love can be a battle and I would like to inspire people with love." The video was shot in November by Norwegian director Ray Kay, who previously directed the videos for Milian's singles "Whatever U Want" and "Say I".

Milian described the video as "very Mad Max versus 300". The video was shot in a desert, featuring Milian and a male love interest, who are the last two people on earth. Milian says, "When you see it, it's nothing like anything you'd see now. I want to be iconic in every music video that I do. I want to make a mark. This is very different."