Mickey Kuhn, a child actor whose long credits list in the 1930s and 1940s included “Gone With the Wind” and “A Streetcar Named Desire,” has died in Naples, Florida, at the age of 90, his wife, Barbara told reporters.

Kuhn was the last surviving credited cast member of “Gone With the Wind,” playing Beau Wilkes, the son of Ashley and Melanie Wilkes, who were played by Leslie Howard and Olivia de Havilland. Kuhn’s most well-known line comes near the end of the film, when Melanie is on her deathbed from pregnancy complications and Beau asks his father, “Where is my mother going away to? And why can’t I go along, please?”

Despite the mother-son relationship between their characters, Kuhn and de Havilland never appeared on-screen together and had never even met on set. In fact, he told the Naples Daily News in 2017 that his first meeting with de Havilland...