With a worldwide audience of millions, viewers were left devastated on Christmas day in 2012 when Dan's character Matthew Crawley (SPOILER ALERT) died following a car accident.The actor is now back, this time on the silver screen, in his first starring role in the Hollywood film The Guest, in which he plays American war veteran David who visits the family of a fallen comrade, but all is not as it seems...Speaking to This Morning's Phillip and Holly, Dan admitted he had no idea whether or not leaving Downton was a good idea but it was something he had to try."It was a total leap of faith, it seemed like a very crazy idea at the time," he said."I knew nothing of what I was going on to do, but when the script for The Guest came along, without really knowing it, I realised it was the kind of film I wanted to do all my life."It sort of celebrates all those movies I loved growing up, The Terminator movies, the John Carpenter movies and it's just really fun, it made me smile from ear to ear."I wasn't really trying to 'make it big' I was just trying to do different things and it's not the kind of movie English boys get to try, but it was a great honour to be embraced as an American in an American film in this kind of action, black comedy mode."The film is definitely a departure from the norm for Dan as he is seen on screen handling weapons and fighting bad guys - something, Phillip noted, audiences would not have seen on Downton."There's fire and guns in the new trailer for Downton - it's very like The Guest!" the actor joked.