Jason Isaacsisn't here for all the muggle back talk. The"Harry Potter"alum, who played Lucius Malfoy in the wizarding drama franchise,weighed in on the controversysurrounding Paapa Essiedu's casting in theupcoming HBO series adaptationof the films. Essiedu, 35, is set to portray Hogwarts professor and Slytherin head Severus Snape, originally played by Emmy-winning actorAlan Rickman. Isaacs, 62, took aim at the racially charged criticism against Essiedu, whose dark complexion differs from that of the original Snape. The British actor, born and raised in London, is of Ghanaian descent. "Paapa Essiedu is one of the best actors I've ever seen in my life," Isaacs said during a July 5 panel discussion at Fan Expo Denver moderated by Collider. "I've seen some people online who are being rude about him. What they're being is racist." Meet your new Harry Potter:HBO series casts Harry, Ron and Hermione HBO's "Harry Potter" series, which does not yet have a release date, will be anew adaptationof thebestselling children's book seriesbyJ.K. Rowling, which was made into a hit film series in the 2000s that starredDaniel Radcliffe,Rupert GrintandEmma Watson. Rowling serves as executive producer on the show. Dominic McLaughlin is set to play orphan-turned-boy-wizard Harry Potter, while Arabella Stanton will play Hermione Granger and Alastair Stout will play Ron Weasley. "All the cast of the new Harry Potter TV series are amazing," Isaacs told Collider. Critics "will be swallowing their tongues, hopefully — you know, their digital tongues — when they see what (Paapa) does on screen." 10 bingeable memoirs to check out:Celebrities tell all about aging, marriage and Beyoncé Essiedu, known for his roles in"I May Destroy You,""Black Mirror"and"The Outrun,"shared his excitement at joining the magical world of "Harry Potter" in an AprilInstagram postannouncing his casting. The actor affectionately signed off the post's caption as "Professor Snape." "An honor and a privilege to be going on this journey with these legends," Essiedu wrote at the time. "We shall eat, and we shall leave no crumbs. See you at Hogwarts." Contributing: Brendan Morrow, USA TODAY This article originally appeared on USA TODAY:'Harry Potter' star slams 'racist' criticism of Paapa Essiedu casting