who plays agent callen on ncis los angeles
G. Callen G. Callen (born: Grisha Alekandrovich Nikolaev) is a fictional character in the show NCIS: Los Angeles portrayed by Chris O'Donnell. He is an NCIS Special Agent in Charge, and the senior agent assigned to the Office of Special Projects. O'Donnell made his first appearance during NCIS' sixth season episode "Legend (Part 1)".
Eric Christian Olsen Eric Christian Olsen (born May 31, 1977) is an American actor. He is known for his portrayals of Detective Marty Deeks on the CBS television series NCIS: Los Angeles, and of Austin in the film Not Another Teen Movie.