After such a long time apart, they reunited for a special episode named Harry Potter 20th Anniversary: Return to Hogwarts, which was full with memories and sadness. Some of the highlights are as follows:
“I used to come in every day and look for his number on the call sheet. It was number seven, and if his name was on the call sheet, it was an extra exciting day,” Emma Watson said.
Chris Columbus was having trouble finding a lead actor for his film. After seeing him in the BBC adaptation of Charles Dickens’ David Copperfield, he chose to cast Daniel Radcliffe.
Tom Felton became teary-eyed when speaking about his on-screen mother, Helen McCrory.
After a battle with cancer, McCrory died in April at the age of 52. “She taught me a lot. See? I can’t even say it,” As he stated this, he began to cry. “She had this ability, yeah, just to sort of show such empathy in her eyes. It was a real treat to work with her.”
Daniel Radcliffe said that he was not pleased with Ron and Hermione’s make-out moment. “I did not make this better because I’ve been told significantly that I was being an absolute dick about this and was like, ‘I’m gonna come on set and watch you guys kiss. I’m sorry about that, guys,” he said. 
The cast constantly assured each other, “We’re family.” “The crew on these films were unbelievable. There are people on these films that are foundational to who I am,” says a teary-eyed Daniel.
“It’s just the best, most amazing experience and that I can’t really explain to you like they’re such good people,” Emma Watson says, her eyes welling up with tears.