BBC America announced that Harry Potter costars Mark Williams (Arthur Weasley) and David Bradley (Argus Filch) will guest star on the upcoming seventh season of science-fiction programme Doctor Who, currently starring Matt Smith as the titular time lord, along with Karen Gillan and Arthur Darvill. Filming began in Cardiff, Wales, this past Monday, and a lucky fan managed to take a photo of herself with Mark on location, which can be seen here.

Plus, new guest stars so far confirmed to star will include David Bradley, Rupert Graves, and Mark Williams.

Season 7 will then see a dramatic turn of events when the Doctor meets a new friend. Prepare yourselves for thrills, adventures and dramatic surprises as the show builds towards its enormous, climactic 50th anniversary year.

Fourteen big, blockbuster-movie episodes — each a brand new epic adventure featuring new monsters and some familiar foes as you’ve never seen them before.