Age: 25
Occupation: Singer
Previous TIME 100 appearances: 1
To gauge Lady Gaga's influence, just look at the numbers. In the past year, the singer became the first artist to reach 1 billion views on YouTube and gain 10 million fans on Facebook. In between grabbing headlines for her sartorial choices like the infamous meat dress, Lady Gaga leveraged her fame for advocacy work too. Last December, the pop star took to Twitter to lobby for the repeal of "Don't ask, don't tell," encouraging her followers to call Senate majority leader Harry Reid. Her third album, titled Born This Way, will be released in May.