In 2000, Momsen taught us all about the real meaning of Christmas as Cindy Lou Who. Seven years later, she scored the role of ambitious teen Jenny Humphrey on Gossip Girl. The star now focuses her energies on her rock band, The Pretty Reckless. "It's less frustrating if someone recognizes me for it; it's more frustrating that I still get asked about it," she told PEOPLE in 2016 about being asked to talk about her CW days. "It feels like someone asking you about junior high. It literally was my junior high, so that's what it feels like to me. It's such a past life that it's a strange question to continue to get asked."
Source : http://people.com/movies/christmas-movie-child-stars-where-are-they-now/