O'Hara played the role of Ella Peterson in the 2010 New York City Center "Encores!" concert presentation of "Bells Are Ringing". She played the role of Ellen in the film "Sex and the City 2" (2010), and in 2011 she appeared in "Mercy", the first episode of the second season of the CBS show "Blue Bloods". Also in 2011, she played the role of Amalia in a benefit concert of "She Loves Me", presented by the Roundabout Theater Company, in honor of the company's 20th anniversary. Scott Ellis directed, and the musical director was Paul Gemignani. She had performed one of the best known songs from the show, "Will He Like Me?", the previous evening at Kennedy Center in honor of Barbara Cook.