And with filming on the final two pictures due to wrap up in 2010, the young actors who spent much of their teen years on set and coping with the superstardom their success has brought are finally looking ahead to life after Potter.

"It was nice to be back and to know that this film is, to me, more of a romantic comedy than ever before and that we would have a chance to focus more on that side of things," said Emma Watson, who plays the feisty bookworm Hermione in the films.

"Sometimes I have to bring myself back with Hermione, because she is so innocent and so naive and she really is very vulnerable in this film," the 19-year-old actress told reporters on Monday at a press conference to publicise the movie.

"She really does get her heart broken by Ron and Lavender and that whole situation."

Director David Yates, who also made the fifth movie "Harry Potter and the Order of the Phoenix", added: "Our cast are just getting that little bit older now and the hormones are starting to fly and for me it marks a real transition point between our cast as children and our cast as adults."

In Half-Blood Prince, out in theatres on July 15, Hogwarts is increasingly vulnerable to attack from Lord Voldemort, wizard Potter's nemesis.

Professor Slughorn, played by Jim Broadbent, joins the cast, and Hogwarts headmaster Albus Dumbledore places more and more trust in his star pupil Potter, determined to prepare him for his inevitable showdown with Voldemort.

Meanwhile, love blossoms, with Harry drawn to Ginny and Ron attracting the attention of Lavender Brown as a heartbroken Hermione looks on jealously.

The first reviews of the movie have been positive.

Variety magazine described it as "dazzlingly well made and perhaps deliberately less fanciful than the previous entries" while The Hollywood Reporter said "a jerky start of exposition and backstory gives way to vigorous storytelling."

END IN SIGHT

The films, the first five of which have earned an impressive $4.5 billion at the box office, are based on British author J.K. Rowling's seven-book Harry Potter series, which has sold an estimated 400 million copies worldwide.

There will be eight films in all, with the final volume, "Harry Potter and the Deathly Hallows", divided into two.

"We're working at the moment on Deathly Hallows, and I think we're all aware that this great juggernaut is reaching the end of its journey in a way," said Yates, who is also directing Deathly Hallows Parts One and Two.

"We finish shooting next spring and everybody comes to work ... with that knowledge in the back of their mind."

According to Hollywood studio Warner Bros., the seventh film is scheduled to hit cinemas in November, 2010 and the eighth in the summer of 2011.

"I'd like to continue acting, really, if I can," said Rupert Grint, who plays Ron.

"It's kind of all coming to an end now and I suppose you've got to start thinking about that kind of thing."

Daniel Radcliffe, who plays Harry and has starred on the Broadway stage, also plans to go on acting.

"Hopefully just keep acting is the plan. I just want to keep going for as long as I can and I've had a fantastic time with Potter. I will be very sad to leave it."

Watson is going to university in the United States.