Kristen Stewart kept it rocker cool while mingling with stars at Rita Ora's pre-Grammy party in Los Angeles on Friday night.The 32-year-old actress hit the red carpet in a vintage Detroit Pistons tee with a large hole in one sleeve. It read 'Just Do It Again' across the front, along with a 'Detroit Bad Boys' logo.The Twilight star finished off her look with cuffed blue jeans and suede lace-up sneakers.She oozed confidence as she flashed a peace sign in the direction of photographers.Stewart's raven shag was styled messily and red-pink eyeshadow made her green eyes pop.