New York - Rapper Kendrick Lamar, one of the big success stories of the Grammys last week, said Thursday his fans should expect 'storytelling' at the Super Bowl halftime show this weekend.Lamar will headline the halftime show at Sunday's showdown between the Kansas City Chiefs and the Philadelphia Eagles, and has announced SZA will join him as a featured guest.He had a clean sweep at last Sunday's Grammys, winning in all five categories for which he received nominations — Record of the Year, Song of the Year, best rap song, best rap performance and best music video.