Spells like teen spirit

Video: Watch the Harry Potter And The Order Of The Phoenix trailer here

'I think we were both a bit nervous, because everyone on set kept teasing us. But, after the first few takes, it was fine.

'In fact, we started to thoroughly enjoy ourselves...' Radcliffe is cut short as Leung, the shy Scottish-Asian who plays Harry's crush Cho Chang, chimes in: 'Yeah, I had so much fun filming it.

'The scene kept being postponed because Daniel said he was ill but he was a good kisser and I'm not just saying that because he's sitting here.'

'And I didn't request 30 takes!' protests Radcliffe. 'No matter what people have said!'

All rather charming, yet, five films down the line, it's going to take more than a bit of PG-rated snogging to get us older punters hot under the collar about yet another Potter film.

Firstly, because Radcliffe's already got his wand out in recent West End show Equus. 'It was something I was very, very proud to do,' he insists. 'Once you've been on stage naked in front of 1,000 people, you really do feel you can do pretty much anything.'

And, secondly, because, if you're a Potter fan, you'll be way more excited about the final book of JK Rowling's series, out on July 21, in which a major character is set to die.

'I'll be very tempted to flick to the back just to check I'm still there,' confesses Rupert 'Ron Weasley' Grint.

However, if there's a slight sense of déjà vu about The Order Of The Phoenix, there are always new faces to whet the appetite. As well as the inevitable new raft of merchandise.

'I was in Waitrose the other day,' says well-spoken Emma Watson (who plays Hermione Granger), 'and I saw a cupcake recipe for Hermione's Magic Muffins. I thought that was a new one.' Considering she's by far the Potter franchise's brightest young star, reportedly playing hard to get after completing Potter Three, we'll doubtless be seeing more of Watson's magic muffins in the future.

Elsewhere, though, the cast members are selected as much for how they fit with their characters as their acting abilities.

The latest Hogwarts recruit, Evanna Lynch, is a besotted Potter fan who came from an open audition. 'There were more than 15,000 trying out for Luna Lovegood,' says director David Yates, 'but you're really looking for someone absolutely natural. That was Evanna. She told us she was the right person to play Luna and if we didn't think so it would really be our problem, not hers, because we would have got it wrong.'

While the now teenage cast have naturally grown into their roles, it helps that the studio has allowed them to do so. However, today they are forbiddingly flanked by a row of 'grown-ups': Yates, producers David Heyman and David Barron, and screenwriter Michael Goldenberg.

When a Finnish interviewer asks the young cast innocently, but amusingly inappropriately: 'What are your expectations of becoming fully blown adults?' Heyman merely rolls his eyes good-naturedly. And everyone giggles.

As they do when someone else asks Radcliffe: 'Have you played yourself in the Harry Potter video game?' Ever the polished young showman, he responds cheekily: 'Very good choice of words. Yes, I've played my... I've played Harry Potter in the computer game.'

Of course life can't be 'natural' when the world is watching you grow up on screen. But it's a learning curve for the new director, too. Previously best known for his TV work, such as Bafta-nominated drama State Of Play and The Girl In The Café, affable director Yates has a lot to prove in taking on the Potter franchise.

Not just the daunting feat of chopping down Rowling's bloated book but also making it read well as a film for fans and newcomers alike.

'Right off we felt this was going to be about Harry's emotional journey, in terms of his conflict with himself and his relationships with his friends, so we took out the Quidditch to make way for that,' he says. However, Yates has come up trumps.

Warner has already signed him up to do Harry Potter And The Half-Blood Prince, a movie he describes as 'all sex, drugs and rock'n'roll. It will be American Graffiti with wands.' Blimey, hold on to your broomsticks. With Harry not only going wet but wild in Harry Potter Six - looks like Harry Potter Seven could well be for adults only.

Harry Potter And The Order Of The Phoenix is released on Friday.