Frederic Wilhelm C.J. Sjöström is an English actor and model of Swedish and German descent, best known for playing Cormac McLaggen in the Harry Potter film series and Luke in the 2012 musical comedy film A Cinderella Story: Once Upon a Song.

In A Cinderella Story: Once Upon a Song, he played the son of a record producer but who actually wanted to perform. It was in this film that he sang the songs Knockin and Possibilities.