Theodore Matthew Michael Kuhn, Jr. (born September 21, 1932), known as Mickey Kuhn, is an American former child actor of the 1930s, 1940s and 1950s. He came to prominence in 1939 playing Beau Wilkes in Gone with the Wind.

Based on this passage, who played beau in gone with the wind? Let's think fast. Stream of consciousness:
The relevant information to answer the above question is: He came to prominence in 1939 playing Beau Wilkes in Gone with the Wind. So the final answer is Theodore Matthew Michael Kuhn , Jr..