Final answer:
Eddie Murphy is the actor who started on Saturday Night Live and starred in Coming to America, The Nutty Professor, Norbit, and gave voice to Donkey in the Shrek series, often playing multiple characters.
Step-by-step explanation:
The actor, comedian, and singer referred to in the question is Eddie Murphy. He started his career as a cast member on Saturday Night Live during the early 1980s. He subsequently starred in a number of successful films, showcasing his ability to play multiple characters in some of them. For instance, in Coming to America and its sequel, Murphy portrayed several different roles. Similarly, in The Nutty Professor he played numerous characters as a result of the main character's family being portrayed by Murphy himself. Moreover, Murphy voiced the beloved character Donkey in the Shrek film franchise.