'Harry Potter' Has Employed 'All My Family,' Emma Thompson Jokes

Thompson's sister, Sophie, is also in 'Deathly Hallows,' which was 'incredible' to shoot, Emma tells MTV News.

Emma Thompson has been so busy with her "Nanny McPhee" films (she wrote and starred in both) that her visit to the "Harry Potter and the Deathly Hallows" set was very brief. When MTV News caught up with the actress to talk about "Nanny McPhee Returns," Thompson said stepping into the shoes of her kooky "Potter" character, Professor Trelawney, for the last time was short but sweet.

"They were very quick," she admitted of her two days on set. "I just had to do a bit of waving of a wand and a bit of 'ooooo-ing' over dead people, because of course they just had to fit absolutely everyone in."

Thompson said the guest-actor-heavy shooting schedule felt like a "conveyor belt of characters, as this extraordinary machine came to its end." Still, Thompson said she made the most of her "Potter" time and was able to reconnect with friends/co-stars she hadn't seen in a while. "It was incredible to see everyone and just sort of quickly say hello and goodbye."

When we mentioned that it seemed like every working actor in the U.K. has appeared in at least one "Potter" film, Thompson heartily agreed. "Absolutely everyone in equity has been in it," Thompson said of the franchise's lengthy cast list. "Including all my family, practically. My sister just finished. I don't know what the name of her character is; she's got a major role in this last one." (Thompson's sister Sophie plays Ministry of Magic employee/ Proper Use of Magic enforcer Mafalda Hopkirk.)

Thompson revealed that she has seen her sister in action, via a photo of Sophie as Mafalda, with Harry Potter (Daniel Radcliffe) himself.

"I've got a photo of her with Daniel dragging her off somewhere ... so I don't know what [they're doing]; I haven't seen it yet."

What scene do you think is in Thompson's photo? Is Sophie a good fit for the role of Mafalda Hopkirk? Share your thoughts in the comments!

Check out everything we've got on "Harry Potter and the Deathly Hallows: Part 1."

For young Hollywood news, fashion and "Twilight" updates around the clock, visit HollywoodCrush.MTV.com.