In 2001, she made her Broadway debut as Becky Thatcher in The Adventures of Tom Sawyer. After moving to Los Angeles, Bell landed various television guest appearances and small film parts before appearing in a lead role in the David Mamet film Spartan. in 2007, she joined the cast of Heroes playing the character Elle Bishop, and Gossip Girl as the off-screen titular narrator. Her mother, Lorelei (née Frygier), is a registered nurse, and her father, Tom Bell, is the television news director for WOAI-TV in San Antonio. Her parents divorced when she was two years old, and she has two half sisters, Sara and Jody, from her father’s second marriage.
