United Kingdom, July 8 -- Jason Isaacs has blasted "racist" fans criticising the cast of Paapa Essiedu in Harry Potter.

The 62-year-old actor - who played Lucius Malfoy in the original film adaptation's of J.K. Rowling's wizarding novels - has called out people taking issue with Paapa being cast as Severus Snape in HBO's upcoming TV series.

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 [Paa...