Daniel Radcliffe Once Wrote a Love Letter to Helena Bonham Carter: 'Wish I Had Been Born 10 Years Earlier'

Nick Wall/HBO Max

It seems magic wasn't the only thing in the air during the Harry Potter films.

During the upcoming HBO Max's reunion special titled Harry Potter 20th Anniversary: Return to Hogwarts, the cast got pretty candid about all the on-set crushes that went on during filming.

While Emma Watson opened up about "falling in love" with Tom Felton when they were younger, Daniel Radcliffe revealed his own crush on Helena Bonham Carter.

In a sit-down between the pair, Radcliffe adorably read a note he had given Carter during filming.

"Dear HBC," Radcliffe began the letter. "It was a pleasure being your costar and coaster in the sense that I always ended up holding your coffee."

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As the two joked about the clever pun, Radcliffe embarrassingly laughed at the rest of the note, before Carter urged him to continue.

"You can share," Carter said, to which Radcliffe added, "I can. I can share this now."

"I do love you," he continued. "And I just wish I had been born 10 years earlier I might [have had] a chance. Lots of love and thanks for being cool."

In addition to Radcliffe's revelation about his crush on Carter, the actor also admitted during the special that some of his first girlfriends and kisses were through Harry Potter.

"Every part of my life is connected to [Harry] Potter," Radcliffe said during the special. "My first kiss is connected to someone here. My first girlfriends were here. It all spirals out from the part of set somewhere."

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Though Radcliffe doesn't name any names, it appears many cast members dated while filming the movies, especially during Harry Potter and the Goblet of Fire which Radcliffe said was "peak hormone."

"There was crushes and people went out with each other and broke up just like you do in school," Matthew Lewis said. "It was exactly the same environment but it was just in a Defence Against the Dark Arts class."

Radcliffe added he would even ask Watson for dating advice, including "prepping and coaching" each other on how to respond to text messages.

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"If she was texting a boy or I was texting a girl, I would be like, 'She sent me this many kisses back. What do I do? This is a nightmare.'"

Harry Potter 20th Anniversary: Return to Hogwarts begins streaming on HBO Max on Jan. 1.