|One Direction's Harry Styles|
A source told the Daily Mirror newspaper: "Believe it or not, Harry hasn't always been 100 per cent confident around the ladies. So when Olly told him about the book, he was gripped straight away and read it in a week.
"Harry has been joking that since reading it, his methods of seduction have become foolproof. His favourite tips are the ones involving talking to hot girls in group situations.
"He now knows it's actually best to ignore the women and focus his attention on the men in order to draw the girls in. Apparently, it works every time."
The 18-year-old singer has most recently been linked to 'Made In Chelsea' beauty Caggie Dunlop after they were spotted cosying up to one another in London's Dorsia club last week, so the handy hints could be working.
The book claims it is "guaranteed to change the lives of men" and some of the key steps of its 11 part theory include: Select The Target, Isolate The Target, Extract Target to Seduction Location.
The source added: "The step he has been really laughing about - and threatening to try out on the 1D lads - is the kissing technique. Harry reckons he has totally nailed it."
Harry is famous for his love of older women and recently joked he prefers cougars to girls his own age, saying: "I'm ready for anything up to my mum's age, she's 44!"
The 'One Thing' hitmaker split from 32-year-old TV presenter Caroline Flack in January and had a brief affair with married DJ Lucy Horobin, 32.