Beginning in 2007, she played the character of Jenny Humphrey in The CW television series Gossip Girl, based on the book series by Cecily von Ziegesar. Momsen’s appearances on the series became increasingly sporadic, and, by the end of the first half of the fourth season, she had only appeared in four episodes. It was then announced that the actress would be scheduled for an indefinite hiatus from the show, which ended with her leaving the series as a regular cast member after the completion of the fourth season in 2011. On August 16, 2011, Momsen told Elle magazine that she had quit acting to focus on her music career. On October 16, 2012, it was reported that Momsen would be returning to Gossip Girl for its final episode, in which she appeared briefly in the wedding sequence.