Oprah shines a spotlight on her all-time smartest and most talented kids, including Willow Smith, on tomorrow’s “Oprah Winfrey Show.” The 10-year-old singing sensation, who released her infectious new single “21st Century Girl” earlier today, will co-host and perform her smash hit “Whip My Hair.” Plus, the pint-sized fashionista shares what’s in her closet. Preview the episode, which also features Lenny Kravitz, below.