Troian Avery Bellisario (born October 28, 1985) is an American actress. She currently stars as Spencer Hastings in the ABC Family series Pretty Little Liars.
Bellisario made her acting debut in 1988 film Last Rites at the age of 3. From 1990 to 2007, She guest starred on Quantum Leap, Tequila and Bonetti, JAG, First Monday and NCIS, television series that were produced by her father Donald Bellisario. In 1998, she co-starred with Mary-Kate and Ashley Olsen in the film, Billboard Dad. Beginning in 2006, Bellisario began appearing in a number of independent short films namely, Unspoken, Archer House and Intersect. In November 2009, Bellisario was cast as Spencer Hastings in the TV series Pretty Little Liars based on the book series of the same name by Sara Shepard.