Jason Isaacs has blasted "racist" fans criticising the cast of Paapa Essiedu in Harry Potter

As reported by Collider, Jason told the crowd at FanExpo Denver: "Paapa Essiedu is one of the best actors I've ever seen in my life.

"I've seen some people online who are being rude about him. What they're being is racist.

"All the cast of the new Harry Potter TV series are amazing. [The critics] will be swallowing their tongues, hopefully - you know, their digital tongues - when they see what [Paapa] does on screen."

Paapa, 35, is following in the footsteps of the late, great Alan Rickman, who played Professor Snape in the original franchise.

He has appeared in the likes of I May Destroy You, Gangs of London and The Lazarus Project.

There have also been questions about his casting because of his and Rowling's opposing views on the issue of trans rights.

However, the author previously clarified: "I don't have the power to sack an actor from the series and I wouldn't exercise it if I did.

"I don't believe in taking away people's jobs or livelihoods because they hold legally protected beliefs that differ from mine."

Jason has also thrown his support behind actor Johnny Flynn, who will take over the role of Lucius.

He wrote on X: "A fantastic actor, a lovely man and, irritatingly, a rather brilliant musician too. Couldn't have handed the snake-topped baton on to anyone better. Just please don't make him sing."

Meanwhile, The White Lotus star recently revealed he's already booked his tickets to see Tom Felton - who played his on-screen son Draco Malfoy in the Potter films - in Harry Potter and the Cursed Child when he reprises his role on Broadway.

Jason wrote on X: "Saw you presenting on the Tonys tonight son - you looked good, sounded good and did great. Tickets booked for November x."

He was responding to a clip of Tom, 37, where he reflected on Jason's performance in The White Lotus.

He told E! News: "He's fantastic. He's superb in everything he does.

"I've learned so much from him - just as much off screen as I have done on screen... I still call him dad and he still calls me son.

"So, hi dad!"