Alex O'Loughlin (Mick St. John)
Was born in Sydney, Australia, 24 August 1975 (some sites give his year of birth as 1976 0r 1977) his real name being Alexander O'Lachlan.
Alex acted in Australian TV and films for a while before coming to the USA where he played Detective Kevin Hiatt in "The Shield".
At the time of writing, Alex is dating Aussie actress Holly Valance (sorry, ladies) who was in "Neighbours", the very long running Australian soap opera.
Apparently Alex was in the running to be the new James Bond, losing out to Daniel Craig!
TV and Films in which Alex has appeared apart from "Moonlight":
The Incredible Journey of Mary Bryant
Black Jack: Sweet Science
The Shield - seven episodes in 2007
The New Guy
The Math of the Wrath
He will also be appearing in a film due for release later in 2008 called Whiteout.