Jason Isaacs Ad-Libbed A Great Harry Potter Line (& Admits Daniel Radcliffe Outdid Him)

Jason Isaacs just shared a fun anecdote from his first day filming Harry Potter and the Chamber of Secrets, and a line that he ad-libbed. Isaacs spoke to Empire Magazine about his new movie The Salt Path, but he spared some time to talk about his other well-known roles, including the villainous Lucius Malfoy. He said that the very first scene he filmed for the franchise was the one between him, Dumbledore (Richard Harris) and Harry (Daniel Radcliffe). It was an enlightening start for Isaacs, who was practically starstruck by Harris, but was still unaware of Radcliffe’s unique talent at that point.

“My first proper day was this scene with the late, great Richard Harris, who I was utterly in awe of, and Daniel [Radcliffe], who I was not yet in awe of,” Isaacs said. “[Daniel] did something remarkable. The last shot was of me leaving. I said, ‘I think I should say something. Lucius is such a proud man. He’s not going to leave without regaining some dignity.’ [Director] Chris [Columbus] said, ‘You come up with something,’ so I said, ‘Let us hope that Mr. Potter will always be around to save the day?’ And Daniel went, ‘Don’t worry, I will be.’”

“He got the last line,” Isaacs recalled. “I thought, ‘F—, he’s good!’” Isaacs has been a very outspoken supporter of the child actors from the Harry Potter franchise as the years have gone on, often making social media posts to promote and support their newer projects. His praise for Radcliffe falls in line with that, but also shows his genuine regard for his younger co-stars.

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Isaacs is currently promoting his own movie, The Salt Path, which is based on a memoir by Raynor Winn. Gillian Anderson plays Raynor, while Isaacs plays her husband, Moth Winn. The two lost their home and Moth was diagnosed with a terminal neurological condition. In the midst of all this, they undertook a 630-mile hike on the South West Coast Path in England. The movie just premiered last week in the U.K., but so far it’s unclear when — or if — it will get a wider release in the U.S.

Isaacs played the Malfoy patriarch in six out of the eight Harry Potter movies, and as the series reboot draws closer, he has fielded more and more questions about that series in recent years. Reporters have had plenty of chances to ask, as Isaacs has had some of his best work to promote, including the latest season of The White Lotus, and his MCU debut in Marvel’s What If…? Nostalgic fans can revisit his performance now on HBO Max.