Daniel Radcliffe used a photo of Cameron Diaz to direct him where to look during broomstick flying scenes in 'Harry Potter'.

The 33-year-old actor - who played the titular character in the movie series based on JK Rowling's books - has previously opened up about his crush on Cameron, and his co-star Tom Felton has revealed how the film crew used it as an aid on set.

Writing in his memoir 'Beyond the Wand: The Magic and Mayhem of Growing Up a Wizard', the 35-year-old star - who played Draco Malfoy - explained how flying scenes were shot using a "see-saw device" and typically "a tennis ball on a long pole" to show where the actor should be looking.

He wrote: "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.

“Sometimes there would be more than one tennis ball up there, and as one looked very much like another, after a while they gave us more individual objects to stare at.

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

Meanwhile, Tom decided to embrace his love for fishing and "chose a picture of an even more beautiful carp".

Daniel hasn't been shy about his early crush on Cameron, and had posters of her on his wall when he was younger.

Back in 2014, he said: "Cameron Diaz was my first celebrity crush. I had pictures of her and Drew Barrymore taped to my bedroom wall."

Earlier this year, Daniel confirmed the duo are still "high" on his list of famous crushes.

Asked for top three, he said: "Cameron Diaz is still very high on the list. Drew Barrymore is there."

And he added: "Juno Temple! I've worked with her, she's gorgeous, and I wouldn't mind saying her name."