It debuted at #1 and is still #1. The fastest selling single ever in iTunes history is Lady Gaga's biggest hit ever. "Ah! Such exciting news! BORN THIS WAY IS #1 FOR THE 5TH WEEK IN A ROW ON BILLBOARD," tweeted Gaga. "This is our biggest hit ever monsters! You are amazing!" Gaga's gearing up to release her second single "Judas" a few weeks leading into the release of her highly anticipated album, Born This Way, due out May 23. Will she top it?