Task: Explanation
Input (English): Alfie Allen (born 12 September 1986) is an English actor. He is best known for portraying Theon Greyjoy in the HBO series "Game of Thrones" since 2011. Question: What English actor portrays the ward taken in by Lord Eddard Stark in the HBO adaptation of the fantasy novel series "A Song of Ice and Fire"? Answer: Alfie Allen
Output (English):  He is best known for portraying Theon Greyjoy in the HBO series Game of Thrones since 2011.