<P> Taylor Michel Momsen ( born July 26 , 1993 ) 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 ) . </P>
who was the girl that played cindy lou who
Taylor Michel Momsen