Released as the album's lead single, "I Kissed A Girl" was a commercial success. It topped the U.S. Billboard Hot 100 chart, becoming the 1000th chart-topper of the Rock Era. The song has since become a major worldwide hit, and along with the United States, it has topped the charts in more than 30 countries, including Australia, Canada, Ireland and the United Kingdom. It was released on 6 May 2008.