John Lithgow speaks out about controversy around new Harry Potter series as first official cast confirmed

John Lithgow has addressed the backlash over his role in the upcoming TV adaptation of Harry Potter.

The 79-year-old actor, best known for his roles in Dexter, The Crown and 3rd Rock from the Sun, was finally confirmed to be taking on the role of Hogwarts headmaster Albus Dumbledore in HBO's upcoming series, following months of speculation.

However, it would seem that some Harry Potter fans aren't too happy about the idea of an American taking the role, given the wizarding franchise's history of casting exclusively British and Irish actors in the films.

Lithgow has now responded to the backlash, revealing to The One Show's Alex Jones that he feels a little 'intimidated' about taking over from previous Dumbledore actor Michael Gambon.

John Lithgow has been officially confirmed as the TV adaptation's Albus Dumbledore (Max Cisotti/Dave Benett/Getty Images)

"Very excited, very intimidated," he told the host, when asked about the role. "I will be following the great Michael Gambon.

"I am not an Englishman, although I've played one on TV. I remind everyone that I did play Winston Churchill on The Crown and I did just fine.

"I know there were plenty of people appalled that an American should be hired to play the ultimate English wizard, but I will do my best."

The role of Hogwarts headmaster was previously played by Gambon, who took over the role after original Dumbledore actor Richard Harris passed away in 2002 after filming The Philosopher's Stone and The Chamber of Secrets.

Lithgow was one of six actors confirmed by HBO to be starring in the series, joining Paapa Essiedu, Janet McTeer, Nick Frost, Luke Thallon, and Paul Whitehouse, who would be taking on the respective roles of Professor Snape, Professor McGonagall, Rubeus Hagrid, Professor Quirrell and Argus Filch.

The Shrek voice actor had appeared to confirm his casting prior to HBO's official announcement in a February interview with ScreenRant back in February, with Lithgow admitting that playing Dumbledore would define the 'last chapter of my life'.

The role was famously played by Michael Gambon (Warner Bros)

"I just got the phone call up at the Sundance Film Festival, and it was not an easy decision because it’s going to define me for the last chapter of my life, I’m afraid," he said.

"I’ll be about 87 years old at the wrap party, but I’ve said yes."

Following the announcement, Frost celebrated the news of his casting by sharing an image of himself holding up one of the books on Instagram, alongside the caption: "You’re a wizard, Harry!!! Thank you for trusting me with such a loyal, gentle and courageous half-giant like Rubeus Hagrid. Robbie, I promise I won’t let you down."

Essiedu has similarly acknowledged the announcement on social media, writing on his own account: "An honour and a privilege to be going on this journey with these legends. We shall eat and we shall leave no crumbs.

"See you at Hogwarts. Professor Snape x."