In the emotion of malu, a person becomes suddenly overwhelmed into awkward silence in the presence of someone who has higher social status. The feeling of being starstruck is something like that, but more specific, and with a different turn of the heart.
First of all, people become starstruck not when they encounter someone with generically superior status, but when they come into contact with someone who has achieved widespread fame.
Secondly, while someone feeling malu will clam up and lose the power of self-expression, a starstruck person is likely to begin gushing, letting lose a stream of verbal adoration, even to the point of shrieking with delight.
