“In the book, Slughorn’s ever-so precious,” Temime said. “But once we had Jim in the part, I thought instead of precious, we’d make him grand.”

“Jim is not a small, fat man. He is tall and strong,” she said. “So we had to change and adapt.”

She explains: “Everything we did for his costumes was very rich, but also very used, because he’s not a rich man anymore. He hasn’t worked for a long time. He is a bit of a has-been. But his clothes, even if they were from 20 years ago, were once upon a time, very rich and very glamorous. So we went for 'Old Glamour' when designing.

“Very pompous, very extreme, very glorious.”

And Slughorn will still be in professors gowns, albeit “very Oxbridge style gowns. With a hat,” Temime said. “That’s very important for him because he’s very proud of being an academic. And it's important he has known students like Harry because they project well on him, and that's how he earns his favors.”

At the same time, Temime said she had to work closely with David Yates to achieve the right balance for the character. “Slughorn has to have power, but at the same time he has to be funny. He has to be overdone, but also be someone you’d respect. It was difficult getting there,” she said.

The solution? “Lots of three-piece suits, classic English tailoring -- but always with a twist. Like fabric that’s a little bit louder, a print that stands out a bit too much. Just little flourishes that show he enjoys the finer things in life.”