LONDON -- If you don't have a fairy godmother, being the belle of the ball can mean a great deal of work.

In Harry Potter and the Goblet of Fire, opening tomorrow, Hermione attends her first Yule Ball, a winter wonderland dance for senior students at Hogwarts.

Hermione may be a witch and have special powers, but Emma Watson, the British teenager who plays her, does not.

She couldn't suddenly learn to dance or even walk properly in a ball gown.

"I didn't know there were so many ways you could walk down stairs until the day we filmed Hermione's entrance into the Yule Ball Hall," says Watson, 15.

"It was difficult and very hard work."

Director Mike Newell was determined to give her an entrance audiences would gasp at as they see the transformation of Hermione into a young woman.

"Mike was giving me all these directions.

"He'd yell: 'Keep your head up.' and 'Make sure your shoulders are back and straight.' By the time we

finished that day, I was a nervous wreck."

Watson hopes her efforts pay off and that "I look OK and it becomes that amazing transformation which it really is for Hermione."

Though she didn't have any input into what Hermione's ball gown would look like, Watson insists "there's nothing about it I would change."

"Jany Temime, who is the head of costuming, created a truly magical dress. I saw its gradual creation because there were so many costume fittings for it."

Hermione's friend, Ron Weasley (Rupert Grint), has a crush on her, but he doesn't ask her to the dance.

To her surprise and delight, visiting Quidditch superstar Viktor Krum (Stanislav Ianevski) does, making her the envy of most of the girls at school.

"I can relate completely to how Hermione reacts when Ron doesn't ask her to the dance and then how elated she is when Viktor does," Watson says.

"Guys can be so insensitive at times and that's what Ron is.

"Hermione thinks she may not have a date for the Yule Ball and that is devastating."

Then she catches Viktor glancing at her.

"What Mike wanted to show was just how insecure Hermione is about herself. She's never had real attention from any boy before and then suddenly the Quidditch star is singling her out and she is quite literally swept off her feet.

"It becomes a quite an emotional roller-coaster ride for her."

Watson concedes playing Hermione in the quartet of films based on J. K. Rowling's best-selling fantasy books has been a similar roller coaster ride.

"It takes 11 months to shoot a Harry Potter film. It's always so exhausting and demanding that I look forward to going back to school and being a regular teenager."

Still, Watson is eager and ready to start working again.

"I love the fun of seeing everyone again. We've always gotten along so perfectly.

"Being back with friends made it easier working on The Goblet of Fire which is quite a dark story."

Watson, Grint and Daniel Radcliffe -- who plays Harry -- have all been signed for the fifth movie, Harry Potter and the Order of the Phoenix, which is set to begin filming in February.

"Though I love playing Hermione, I definitely don't want Harry Potter to be the last thing that I do in this business," Watson says.

"Originally, what I love doing and wanted to do was stage work, because I love the reaction of a live audience. So maybe my calling is more in theatre than film.

"I'm not positive because there are so many things that you can do as an actor, so I'm always looking around and considering my options."