Daniel Radcliffe has reached out to the young actor taking on the lead role in the upcoming Harry Potter TV series.

In an interview on Good Morning America, the actor, who played Harry Potter across eight films, revealed that he had penned a letter to Dominic McLaughlin as he prepared to portray the lead character in the new show.

"I know a few people working on the production," Radcliffe shared. "I wrote to Dominic and sent him a letter, and he sent me a very sweet note back."

Radcliffe added that he didn't "want to be a spectre in the life of these children" but wrote him the letter to say, "'I hope you have the best time, and an even better time than I did - I had a great time, but I hope you have an even better time.'

"And I do, I just see these pictures of him and the other kids and I just want to hug them," he continued. "They just seem so young. I just look at them and say, 'Oh it's crazy I was doing that at that age.' But it's also incredibly sweet, and I hope they're having a great time."

Alongside McLaughlin, Arabella Stanton has been cast in Harry Potter as Hermione Granger, and Alastair Stout as Ron Weasley.

Other actors on the show include Paapa Essiedu as potions master Snape, John Lithgow as headmaster Albus Dumbledore, Janet McTeer as Minerva McGonagall, and Nick Frost as Rubeus Hagrid.