Complex sentence: A star is an actor or actress, often a popular one, who plays a central character in a film, but occasionally the word can also express fame of members of the crew, such as a director or other personality, such as Martin Scorsese.
Split into simpler sentences: A star is an actor or actress, often a popular one, and in many cases, a celebrity who plays a central character in a film. Occasionally the word can also be used to refer to the fame of other members of the crew, such as a director or other personality, such as Martin Scorsese.