By Caroline Briggs
Entertainment reporter, BBC News
Dark clouds are gathering over Hogwarts in Harry Potter and the Order of the Phoenix.
The three actors have starred in the films since 2001
The fifth film to be adapted from JK Rowling's books - released on 11 July - is the grittiest yet, as Harry battles with the angst and growing pains of teenage life.
And while the film echoes the growing age of the young cast, actors Daniel Radcliffe, Emma Watson and Rupert Grint will be wearing school uniforms for at least another two years.
Rowling brings the magical saga to an end in Harry Potter and the Deathly Hallows, published on 21 July.
It will mark the finishing line for the trio, who have played Harry Potter, Hermione Granger and Ron Weasley since 2001.
Radcliffe, 17, says he has no idea what to expect from the final book, but has pre-ordered a copy.
"We can sit here and talk about it but Jo is coming to come up with something far more interesting or exciting than anything we can predict and imagine," he says.
Rowling has already hinted that two main characters will die in final instalment, but has not revealed who.
Watson is tempted to take a sneaky peek to see if it is Hermione who meets a sticky end.
"I hope Hermione doesn't die - I really didn't have that in my plan for what she would achieve," she says.
"I want to see her putting her intellect and her very caring nature to some very worthy cause - going around the country protesting for the rights of house elves, or continuing with SPEW and generally making the world a better place. Being married to Ron and having beautiful babies."
Grint, 18, is more succinct: "If Ron had to die it wouldn't be so bad - it's the last one anyway."
The latest Harry Potter film is the fifth in the series, and sees the franchise's fourth director at the helm, with David Yates following in the footsteps of Christopher Columbus, Alfonso Cuaron and Mike Newell.
Daniel said he enjoyed portraying Harry's troubled teenage years
Yates, best known for TV dramas such as The Girl in the Cafe and State of Play, has combined aspects of previous films with his own take on Harry's character, explains Radcliffe.
"I think this is the film I'm most proud of and we had a great time working with David," he says.
"He has taken the charm of the films that Chris made, the visual flair of what Alfonso did, and the thoroughly British bombastic nature of the fourth film, and added his own sense of grit, and realism to it that perhaps wasn't there so much before."
Watson, 16, says it is the most "genuine" of all the films.
"The word I connect the most with David Yates is 'truth'," she adds.
"He always wanted to find truth in all the characters. We really relished that and it stopped us getting complacent."
Radcliffe says one of his greatest challenges was tackling the more troubled and complex side of the teenage Harry.
"I talked to Jo (Rowling) about it, and she said if people say they don't understand why he is angry then they have not understood what he has been through in the last five years," he explains.
"He has a right to be angry. For me it was just as interesting to play the reflective side of the anger, where it comes from like the loneliness and feeling misunderstood, than the out-and-out shouting that people may have interpreted from the book."
It was Gary Oldman, who plays Harry's godfather Sirius Black, who inspired him.
"Me and Gary got to do some really emotional and heartfelt scenes together, which was great," Radcliffe says.
Hermione and Ron sign up for Dumbledore's Army
"I have been a fan of his for a long time, and I think anybody would be hard-pushed to name another actor whose body of work covers so many different areas. I think he is incredible."
The Order of the Phoenix also stars Oscar-nominated Imelda Staunton as Defence Against the Dark Arts teacher Dolores Umbridge, and Helena Bonham Carter as the demented Bellatrix Lastrange.
It also sees Radcliffe share his first on-screen kiss.
But kissing Katie Leung - who plays fellow Hogwarts pupil Cho Chang - was easy compared to stripping off on stage, as he did in the West End play Equus.
"Once you've been on stage naked in front of 1,000 people you really feel you can do almost anything without inhibition," he laughs.
"Being naked was possibly not as complicated as kissing - although belt buckles can give everybody a bit of trouble at times - but kissing Katie was a very, very comfortable experience, especially when compared to being naked on stage and blinding horses."
Leung, 19, who won the part of Harry's girlfriend after an open audition, says he was a "good kisser".
"I only watched the film yesterday and I thought I'd be cringing, but I'm very pleased with it. It's a very endearing and sweet scene," she says.
"I'm not sure how my mum and dad are going to react. Hopefully they will find it really sweet as well."