The `Debt` hunk rarely gets recognised by fans but admitted ever since he grew a beard people are confusing him with the portly `Hangover` star.
He explained: "I get recognised more at the moment because I`ve got a beard and people think I`m Zach Galifianakis. They go, `Hangover 2 rocked, dude!`
"But in reality I`ve always been able to go under the radar. I had a big career in Australia but I could still go out to the local bar."
Sam split from his girlfriend of three years Natalie Marks in October, but although he insists he would never use his fame to chat up women, his friends don`t have the same scruples.
He told Shortlist magazine: "My mates exploit [my fame] all they can. They always exploit it."
Sam has made 10 films in four years and is now ready to take some time out to enjoy his success and do "f**k all".
He said: "I`ll be doing f**k all. Nothing. That`s what I`m looking forward to; sitting on a beach, doing nothing, walking the dog - I`ve got a King Charles spaniel crossed with a bijon called Bacon - and figuring out what I want to do."