a musical play (1935) by George and Ira Gershwin which has been called 'America's first folk opera'. It was based on the 1925 novel Porgy by Dubose Heyward, and is about poor African Americans in Charleston, South Carolina. The main characters are the lovers Porgy, who lives by begging, and Bess. Its best-known songs are Summertime, I Got Plenty o' Nothing and It Ain't Necessarily So. Sidney Poitier and Dorothy Dandridge were the stars of the film version (1959).