Joshua Herdman (Gregory Goyle) is the latest addition to the line up for Muggle Mayhem, a fan convention that will be held in Northhampton, England this weekend. Also attending are Potter actors William Melling (Nigel), Genevieve Gaunt (Pansy Parkinson from Prisoner of Azkaban), Robbie Jarvis (young James Potter), and Nick Shirm (Zacharias Smith).

Additionally, Natalia Tena (Nymphadora Tonks) is scheduled to perform with her band on Saturday.

All proceeds from the event will go to support the charity, Multiple Sclerosis Scotland.

The event takes place from August 7 - 9 at the Park Inn, Northhampton.

For more details and ticket information (children under age 7 are free), click here.