Goalkeeper Charles – who plays his club football for Sheffield Wednesday – put in a strong performance in nets for the U21s as they beat Serbia away from home back in March.
Charles, younger brother of Northern Ireland midfielder Shea Charles, has trained with the senior squad before, however this is his first official call-up to the seniors. The teenager has previously played for his country at U17, U19 and U21 level.
O’Neill believes the 18-year-old has all the traits needed for a goalkeeper to shine in the modern game.