Who is playing Merope in Harry Potter and the Half-Blood Prince?

Merope Gaunt is not a character that appears in "Harry Potter and the Half-Blood Prince". She is a character from the earlier books in the series, specifically "Harry Potter and the Half-Blood Prince" where she is portrayed by Helen McCrory as a young woman and Shirley Henderson as an elderly woman.

While Merope is not physically present in the film "Harry Potter and the Half-Blood Prince", she is a significant figure in the story as it delves into the history of Tom Riddle and the origins of Lord Voldemort.