Complex sentence: Watanabe does impersonations of popular artists in Japanese culture, among which her imitation of Beyoncé Knowles singing "Dreamgirls" and "Crazy in Love" quickly became popular.
Split into simpler sentences: Watanabe does impersonations of popular artists in Japanese culture. Among her impersonations, her imitation of Beyoncé Knowles singing "Dreamgirls" and "Crazy in Love" quickly became popular.