Tom Felton says he's still 'ashamed' that he once laughed at a 9-year-old Emma Watson for dancing on the set of 'Harry Potter'

Felton recalled an example of the "Gryffindor/Slytherin divide in the early days" in his new memoir titled "Beyond the Wand," released on Tuesday.

• Tom Felton recalled being insensitive toward "Harry Potter" costar Emma Watson early in the franchise.
• "There was a definite Gryffindor/Slytherin divide in the early days," Felton wrote in his memoir. 
• He recalled Watson being "visibly upset" by Felton and a costar snickering as she danced on set.

"Harry Potter" star Tom Felton said that he's still mortified by the memory of him making fun of Emma Watson dancing on the set early in the franchise. 

Felton detailed the evolution of his relationship with Watson, who's now one of his closest friends, in his new memoir released on Tuesday, titled "Beyond the Wand: The Magic and Mayhem of Growing Up a Wizard."

Felton and Watson are known for their roles as Draco Malfoy and Hermione Granger, respectively, in the "Harry Potter" films, based on a fantasy-book series penned by J.K. Rowling. Felton first met Watson at the auditions, when he was 12 and she was 9.

"There was a definite Gryffindor/Slytherin divide in the early days," Felton wrote. "Two cliques that kept their distance from each other, largely because we didn't spend that much time working together."

One group was comprised of the main "HP" trio of Daniel Radcliffe (Harry Potter), Rupert Grint (Ron Weasley), and Watson. The other clique consisted of Felton and his on-screen best friends and fellow Slytherins Jamie Waylett (Vincent Crabbe) and Josh Herdman (Gregory Goyle).

Felton said the two clans "weren't unfriendly to each other by any means," but there were differences in their upbringings and tastes. 

"I suppose we thought we were a bit cooler," Felton wrote. "We'd spend our free time together listening to rap music — Wu-Tang, Biggie, 2Pac — so when word reached Josh and me that 9-year-old Emma had put together a little dance show in her dressing room that she wanted to present to us at lunchtime, we were predictably dismissive."

"We sniggered our way down to Emma's show, and the sniggers grew louder as she danced," Felton recalled. "We were just being shitty boys, largely out of awkwardness and because we thought taking the piss was cool, but Emma was visibly upset by our thoughtless reaction. I did feel like a bit of a dick, and rightly so."

Following a conversation with one of the women from the hair and makeup department, the actor said he apologized to Watson. 

"I did apologize and Emma accepted my apology," Felton recalled. Everybody moved on. It was just a stupid, teenage act of thoughtlessness, the sort of thing that happens every day. So why does that moment stick in my memory? Why is it so painful for me to recall?"

"The answer, I think, is that I've grown to understand with the passing of the years that of all of us, Emma had the most to deal with, the most difficult situation to negotiate, and from the earliest age," he said.

Felton said that "Harry Potter and the Sorcerer's Stone," released in 2001, marked Watson's first time on a film set and she was the only female lead, surrounded by "boy humor." When the franchise's popularity exploded, she suddenly became pushed into the spotlight and subjected to a different kind of scrutiny than her male costars.

"And the pressures she experienced went further than just having to deal with stupid boys," he continued. "Emma was never afforded a normal childhood. She was in many ways treated like an adult from the day she was cast. It's a phenomenon that can, I think, be more difficult for girls than for boys. They are unfairly sexualized in the media and beyond."

Felton went on to say that "the last thing she needed, in an environment that should have been — and normally was — safe and friendly and familial, was Josh and me laughing at her dance."

"That's why I feel ashamed by the memory of our behavior," he said. "And that's why I'm glad that our friendship did not founder on the rocks of my insensitivity, but became something deeper. A touchstone for both of our lives."