A Scottish television and film actor and director. He is known for his prominent television roles, including his performances as Lucius Vorenus in Rome, as Poseidon in Percy Jackson & the Olympians: The Lightning Thief, and as Dr. Owen Hunt in Grey's Anatomy. He has also appeared in films such as Trainspotting, Bedrooms and Hallways, Kingdom of Heaven, The Last Legion, Hannibal Rising, The Acid House, Made of Honor and had the lead role in the cult-classic British horror film Dog Soldiers.