Katy Perry has cemented her status as a best-selling superstar with the global success of her second studio album, Teenage Dream, which debuted at #1 in 8 countries. All 4 singles released so far ("California Gurls," "Teenage Dream," "Firework" and "E.T.") have hit #1 on the Billboard Pop Songs chart, making hers just the third album in the 18-year history of the chart to yield a quartet of No. 1s. She also holds the distinction of being only the ninth album in the 52-year history of the Billboard Hot 100 chart to produce four No. 1s. This follows on the heels of her multi-platinum debut album, One of the Boys, which generated four hit singles: "I Kissed A Girl," "Hot N Cold," "Thinking of You" and "Waking Up In Vegas." She wrapped up 2010 in style with 4 Grammy nominations, including one for "Album of the Year." Katy kicked off 2011 with sold-out shows on the European leg of the California Dreams Tour, and will play sold-out shows in Australia, New Zealand and Japan before heading to North America and beyond.