Julian Dana William McMahon (born July 27, 1968) is an Australian actor, former model, and the son of a former Prime Minister of Australia, Sir William McMahon.

He is best known for his roles as Detective John Grant in Profiler, Cole Turner in Charmed, Christian Troy in Nip/Tuck, Doctor Doom in the Fantastic Four franchise, Jonah in Marvel's Runaways, McCarthy in Hunters, and Jess LaCroix in the CBS crime drama FBI: Most Wanted.

His movies include Premonition (2007), RED (2010), Paranoia (2013), and You're Not You (2014).