Harry Potter star Emma Watson's new sexy look has earned her the Sexiest British Actress Under 30 title.

The 20-year-old beats British beauties Keira Knightley, Sienna Miller and Gemma Arterton in this poll, which was conducted by Fandango.com, reports torontosun.com.

Watson cast a spell on her fans when she arrived for the world premiere of the latest Harry Potter movie in a skimpy black lace mini-dress, a marked contrast to the prim and elegant outfits she has worn at the six previous Potter first nights.

Is it a coincidence or are super short bobs sexy?

After Emma, it is Keira Knightley, who came second in the poll after chopping off her locks. She debuted the sleek new 20s-style bob at the Chanel spring/summer 2011 show during Paris Fashion Week.

'I had my hair bobbed about a month ago, then I had it freshly trimmed again this morning,' Us magazine quoted Knightley as telling UK InStyle.

The new 'do wasn't for a movie role, I did it for myself,' she added.

Emily Blunt's good looks landed her the third spot.

The actress recently confessed her disliking for airbrushing, saying that it makes her look like a barbie.

The 27-year-old, who has done films The Devil Wears Prada and Young Victoria, says she prefers a more natural look.

'I don't like it when they stretch you out and make you all long and skinny,' the Telegraph quoted her as telling Elle magazine. 'It makes you look like a Barbie. Who the hell looks like that?' she added.

The British actress, who is more famous for her on and off again relationship with actor Jude Law, showed off her enviable toned figure in a skimpy bikini recently, thus snaring her the fourth spot on the list.

The English actress once revealed that she does not think she was hot enough to be a Bond girl.

Arterton, 24, who acted in Quantum Of Solace, told GQ magazine that she thought herself to be an 'average' girl.

Looks like her fans disagree.

After Emma Watson, another Harry Potter star makes it to the sexy list.

Wright, 19, who plays Ginny Weasley in the Potter series, recently revealed that she loves to dress up for the red carpet and admits she'd wear some of her own designs one day.

'I see the red carpet as an opportunity to show people the real me,' Contactmusic quoted Wright as telling Grazia magazine. 'My character is perceived as the mousy younger sister and it's nice to break away from that -- but it took me such a long time to decide what to wear.'

The 28-year-old actress is not only easy on the eyes, but she can act as well.

Her best performances include The Prestige and Vicky Cristina Barcelona, for which she was nominated for a Golden Globe in the Best Actress in a Motion Picture -- Musical or Comedy category.

The 24-year old Oscar nominated actress looks more like a school kid in her short cropped hair rather than a sexy vixen. But, hey, try telling her fans that.

Yet another Harry Potter star makes it to the list.

This time it's Scottish actress Katie Leung, better known as Harry Potter's on-screen love interest.

Besides her sex appeal, the 20-year-old is known for her sense of style, which earned her the title of Scotland's Most Stylish Female of 2007.

We don't blame you if you're not familiar with this 28-year-old who made her big screen debut in Woody Allen's 2007 film Cassandra's Dream.

But come 2011, you will know her as Peggy Carter, the romantic interest and former WW2 French Resistance fighter, in the comic book adaptation of Captain America: The First Avenger.