"Harry Potter" star Tom Felton is spilling the details on his co-star Daniel Radcliffe’s celebrity crush. 

In Felton’s new memoir, "Beyond the Wand: The Magic and Mayhem of Growing Up a Wizard," he shared that Radcliffe used a photo of Cameron Diaz to help guide him on where to look while filming the flying broomstick scenes. 

"The approach was that if a piece of magic or any kind of special effect could be achieved practically, that was the best way to do it," Felton explained, according to excerpts shared by Insider.  

"This was especially true in the early days when the visual effects team had less-advanced technology at their disposal."

EMMA WATSON CALLS 'HARRY POTTER' CO-STAR TOM FELTON HER 'SOULMATE' IN HEARTFELT FOREWORD TO HIS BOOK

Felton portrayed Draco Malfoy in "Harry Potter" – Radcliffe’s nemesis in the mega-hit franchise.

Daniel Radcliffe, Cameron Diaz

"Harry Potter" star Tom Felton revealed his co-star Daniel Radcliffe’s celebrity crush. (Getty Images)

The fantasy sport, Quidditch, was popular among the wizards and witches in the world of "Harry Potter."

The cast of Harry Potter

In the memoir by Tom Felton, left, he shared that Daniel Radcliffe, center, used a photo of Cameron Diaz to help guide him on where to look while filming the flying broomstick scenes. (Dimitrios Kambouris/WireImage via Getty Images)

The actors would create the flying scenes in front of a blue or green screen, and the background would be added in post-production. 

"The broomstick was a metal pole fitted with a deeply uncomfortable bike saddle," Felton recalled.

tom felton

Tom Felton portrayed Draco Malfoy in "Harry Potter" – Daniel Radcliffe’s nemesis in the mega-hit franchise. (Dave Hogan/Getty Images)

"There were stirrups for your feet and a harness to stop you falling. They strapped you to the pole, so you couldn't fall, and they had a more elaborate see-saw device to move you up and down, left, and right. They blew fans in your face to make it look as if you had the wind in your hair."

EMMA WATSON, TOM FELTON AND MORE 'HARRY POTTER' STARS REUNITE FOR HOLIDAY PHOTO

To maintain continuity while filming the Quidditch scenes, a crew member would hold up "a tennis ball on a long pole with orange tape on it," and the actors were advised to look in that direction. 

"When the first assistant director shouted ‘Dragon!’ or ‘Bludger!’ you had to look at the tennis ball like it was, well, a dragon or a bludger," Felton described.

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The 35-year-old actor explained that since there were multiple tennis balls during some scenes, they were directed to stare at individual objects to avoid confusion. 

"We chose pictures of something or somebody close to our hearts. Daniel Radcliffe had a picture of a particularly beautiful Cameron Diaz."

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Meanwhile, Felton revealed his photo choice was a "beautiful carp" since he enjoys fishing.