Taylor Momsen performed the live action version of Cindy Lou Who in How the Grinch Stole Christmas!. (born July 26, 1993)[1] is an American singer, songwriter, former actress, and model. She is known for being the lead singer and frontwoman of the American rock band The Pretty Reckless. She is also known for portraying the character of Jenny Humphrey on the CW teen drama series Gossip Girl (2007–2012) and Cindy Lou Who in the film Dr. Seuss' How the Grinch Stole Christmas (2000).[2]