Time waits for noone and things have changed for Daniel Radcliffe and Emma Watson since the first Harry Potter film burst into the public consciousness four years ago.
Greeting the press the day after the world premiere of Harry Potter and the Prisoner of Azkaban in New York, there is a quietly eloquent maturity in these two 14-year old, British stars.
Radcliffe is sporting a white t-shirt and jeans, while a glowing Watson wears a sparkling red outfit out of Sgt. Pepper. Full of smiles, the pair agree they have developed over the three films, but don't know exactly how.
"We have just been getting older and maturing", a reticent Watson begins, now waiting for her male counterpart to finish her thought. Adds Radcliffe on cue. "I think we probably have changed as actors but I'm not conscious of myself changing. I haven't watched the first film for about three years now, so I can't really compare it to the third because it's not very fresh in my mind," he says. But both admit their confidence has increased throughout the three films, Radcliffe says. "Just because we're really more experienced with different directors."
The different director Radcliffe refers too is Mexico's Alfonso Cuaron, who replaced America's Chris Columbus for the much darker Harry Potter and the Prisoner of Azkaban. Comparing the two, says Radcliffe, stems from what the pair learnt initially with Columbus.
"Basically I think, everything we learned with Chris, we were now able to put into practice with Alfonso", says Radcliffe. "The reason why he was able to do longer takes and more complicated shots, was because with Chris we just didn't have the experience or the focus to do that kind of stuff. And it is harder and more challenging, because we're getting older and so if we're not getting challenged there's really no point in doing it."
In Prisoner of Azkaban, Radcliffe may be the title character, but it's the blossoming Watson who ultimately dominates the fourth adventure, punching her nemesis in the nose and virtually saving the day.
"I refer to it as my kind of girl power", Watson laughingly exclaims.
Continuing on that theme of the prevalence of girl power in Prisoner of Azkaban, Emily says she hopes she did the character justice this time around, "because it's my favourite book and such a great part for her, so I hope that she's what they all thought she'd be."
She adds that Hermione "finally comes into her own in this one. I think you see a really different side to her than you had in the other two. I think her journey is much more personal and this film has really tested me."
But with that maturity, comes with it growth as adolescents and hormonal change. Both actors laugh when asked about the state of their love lives, admitting, in unison, that they don't have one. "Sorry to disappoint you", laughs Radcliffe. But of course both teenagers have become increasingly aware of, let's say, the opposite sex, Radcliffe shyly concedes.
"I'm sure both of us have noticed members of the opposite sex, because we're both fourteen going through what any teenager is going through." Daniel does admit, however, that he has begun noticing young women noticing him more.
"I'm not complaining", he adds laughingly. On their down time, with hormones chasing them in all directions, Radcliffe overcomes his hormonal frustrations, he says, by "listening to a lot of rock music" in between takes. Then he smilingly adds. "Hormones are very interesting things and the music definitely helps let off a little steam."
Nor are they complaining about leaving behind some aspect of their childhood, shooting the Potter films, such as a conventional school life. "I do better at school when I'm on set", Radcliffe concedes. "I get to see all of my friends without having to do all the work."
All three of the teenagers are about to begin Harry Potter 4 under the direction of Mike Newell, but beyond that, neither Radcliffe nor Watson are prepared to disclose whether audiences will see these actors beyond a fourth adventure.
"Each one takes a year to do, so it's something I'm not focussing on", says Radcliffe.
"One film at a time", Watson adds laughingly.
Yet if age catches up with the teenagers Radcliffe does admit it would be tough handing the role to another actor. "In my mind it would be very hard to watch someone else play the parts, but the reality is, we are getting older."
Of course for both actors, there is life and ambition beyond the Potter films. Radcliffe says that he really enjoys acting. "I love it and I think it's really something I want to go on with, but I also want to develop my music and writing."
As for Ms Watson, "I feel incredibly lucky to have been given the opportunity to have been in such a fantastic film. I mean my ambitions could not have even dreamed of the scale and greatness that Harry Potter is", enthuses the diplomatic young actress.
"But I love performing and being creative. There are so many different aspects of the film world that even if I don't pursue the acting, there's something else I'm bound to end up doing. I'm just going to go with the flow and see what happens."