Rihanna and her halftime show team was "very careful" not to reveal she was pregnant before the Super Bowl last weekend, the director of the show said this week. "She was very careful about who knew," Hamish Hamilton, who has directed the halftime show since 2010, told "Entertainment Tonight." "And we only knew, really, at the very latest stages. Her and her team carefully managed that, and we obviously also then carefully managed that." The "Rude Boy" singer became the first pregnant woman to headline a halftime show when she appeared on a platform more than 60 feet above the field on Sunday cradling her baby bump.