voice–over 
/ˈvoɪsˌoʊvɚ/ noun
plural voice–overs /ˈvoɪsˌoʊvɚ/ noun [count] : words that are spoken in a movie or television program by a person who is not seen
▪ He does a lot of voice-overs [=narration] for commercials.
▪ He does a lot of voice-overs [=narration] for commercials.
