A teenage actor from the Harry Potter films was charged on Tuesday with illegally growing 10 cannabis plants, British police said, shortly before the world premiere of the latest movie.

Jamie Waylett, 19, who plays schoolboy bully Vincent Crabbe, will appear at Westminster Magistrates Court in central London on July 16 "charged with producing a class B drug, namely 10 plants of cannabis", police said.

Waylett, from north London, appears as the overweight, greedy and dim-witted side-kick of villain Draco Malfoy in all of the films about boy wizard Harry.

The charge was announced just hours before the Potter stars walked up the red carpet in London for the world premiere of the sixth film, Harry Potter and the Half-Blood Prince.

The pre-release buzz suggests the new movie will add a sizeable chunk to the $US4.5 billion ($5.65 billion) in box office receipts already earned by the successful Potter movie franchise.

AFP