Jennifer Lopez made a grand entrance at the Grammys in LA tonight wearing a sexy slitted gown by Anthony Vaccarello. She arrived on the arm of boyfriend Casper Smart, and the duo posed for photos on their way down the carpet. J Lo isn't nominated at this evening's show, but she will be taking the stage to present an award. Other presenters include Beyoncé Knowles, Faith Hill, and Keith Urban. They won't be the only famous faces in the spotlight, since Taylor Swift and Carrie Underwood are expected to perform and many other big musical names are up for honors. Make sure to check out our LIVE Grammys show, and vote on your red carpet favorites in our fashion and beauty polls!