Hemsworth, 23, who is currently shooting for "The Hunger Games", likes to keep his relationship private and doesn't want his silence to be taken as something against Cyrus.
"He has no surprise at all for her continued success. That is one of the things Miley had that originally attracted him," showbizspy.com quoted a source as saying.
"He is very proud that she is doing the thing that she loves and he supports her, he just doesn’t broadcast it with a parade for the whole world to see. He likes being private with her and their relationship, where as she doesn’t. But you know what they say, opposite’s attract," the source added.