Emma Watson and Justin Bieber had the most influential haircuts of 2011. The actress' pixie crop and the singer's 'swish' style have been hugely popular with fans over the past 12 months, with hairdressers all over the world being inundated with requests for something similar.

"Hairstylists are being inundated with requests. The enthusiasm plays out online, where the fastest-rising searches for celebrity haircuts on Google are for Ms. Watson and Mr. Bieber," The Wall Street Journal reported.

According to the paper, these looks mark a pretty significant change for hairstyle popularity, since for women, "short hair hasn't been trendy since the '90s" and because men "may justifiably feel sheepish about asking for the cut."

Emma, 21, had her hair cut at the end of last year and said it was a way of entering a "new phase" in her life as she had finished playing Hermione Granger in the Harry Potter film franchise: "I'm 20 now, so I'm not a child any more. I've been on Harry Potter for ten years now, so I felt the need to mark the end of it in some way - I needed some way to say to myself, 'Right, you're entering a new phase of your life now.' I needed a change, and that's what the haircut is about."