Harry Potter star Tom Felton has apologised to fans after pulling out of a major film convention in Canada to shoot a new movie.

The British actor had been billed as one of the star guests at the upcoming Fan Expo Canada in August (13), but he will no longer attend the annual event due to a scheduling conflict.

In a post on his Twitter.com page, Felton writes, "I'm really sorry to have to cancel my expo dates in Canada this year. I was really looking forward to it... have fun! Duty calls..."

Comic book icon Stan Lee, Game of Thrones actress Lena Headey, The Walking Dead's Norman Reedus and Star Trek legend George Takei are among the famous faces who will appear at the summer gathering in the Metro Toronto Convention Centre.