Justin Chatwin (born October 31, 1982) is a Canadian actor. He began his career in 2001 with a brief appearance in the musical comedy Josie and the Pussycats. Following his breakthrough role as Robbie Ferrier in the blockbuster War of the Worlds (2005), Chatwin headlined studio films such as The Invisible (2007) and Dragonball Evolution (2009), an action-adventure feature based on the manga series Dragon Ball. In the 2010s, Chatwin acted in small independent films. He starred as rock star idol Bobby Shore in the sci-fi musical Bang Bang Baby (2014), which earned him a Canadian Screen Awards nomination for Best Supporting Actor and appeared in the romantic comedy Unleashed (2016) and drama Summer Night (2019).

Throughout the 2000s, Chatwin made guest appearances in several television series, including Weeds and Lost. His first regular role was on the comedy-drama Shameless, where he portrayed Jimmy Lishman between 2011 and 2015. Chatwin starred as a cartoonist in the CBS murder mystery drama American Gothic (2016), and also that year, he appeared as superhero Grant Gordon / The Ghost in the Doctor Who Christmas special "The Return of Doctor Mysterio". From 2019 to 2021, Chatwin played scientist Erik Wallace in Netflix's Another Life.