Britney Spears wore pink to a dance studio in West Hollywood yesterday. The pop star debuted her new single, "Hold It Against Me," on Monday, and it reached number one on iTunes within hours. The majority of you love the track as well as the cover art. Britney's been prepping for the big release, and took to Twitter to thank her fans for their support. She's now back working on her dance moves, but contrary to reports, she won't open the Grammys.