Star Wars director JJ Abrams said he wanted to make female characters a central part of The Force Awakens so it would "feel the way the world looks and feels".
In addition to main character Rey, played by Daisy Ridley, the film also stars Lupita Nyong'o as pirate Maz Kanata and Gwendoline Christie as evil Phasma - as well as female Stormtroopers and pilots.
Abrams said: "From the very beginning of our discussion about this movie, the notion of a woman at the centre of the story was always something that was compelling to me and exciting.
"Not just at the centre, but it was important that in addition to Leia (Carrie Fisher), who we knew was a critical piece of this puzzle, that you wanted to have other women and female characters in the story."
At a press conference with the stars of the film on the day of its UK release, the director added: "We just wanted this thing to not feel like it was not inclusive.
"We always wrote Rey as this central character, but as we started casting this movie it just felt like one of the things we knew we wanted to do, and make the film look and feel the way the world looks and feels."
Christie spoke about seeing her costume, designed by Michael Kaplan, for the first time.
She said: "I was really astounded by how extraordinary it looked. Also that it was practical.
"And I loved the fact that it hadn't been feminised in any way, it hasn't been sexualised in any way, it was practical armour.
"And what I got from the costume was that this was a woman who was imposing, uncompromising and high functioning."
Meanwhile, Harrison Ford said he wants nothing to do with the "young Han Solo" origins film which was announced in the summer.
On the movie, which is apparently due to start filming in 2017, he said: "I don't know even what to think of that. I'm glad that someone else is going to have the burden of being young.
"It's well beyond my understanding or control and I of course want nothing to do with it."
The actor, 73, who returned for The Force Awakens after playing Solo in the original three films, said he enjoyed filming the latest movie more than he expected to - despite previously saying he wanted his character to be killed off.
Ford said: "I have actually relished this entire experience in a way that I had not anticipated. I think a lot of the credit for that goes to JJ and Larry (Kasdan, the writer).
"This is a rare experience in my whole life and I'm very grateful for it."
Newcomers John Boyega and Daisy Ridley told of their unique experience at suddenly becoming famous.
Boyega, who plays Finn, said: "Recently we went to Tokyo and the first thing we saw was a 7/11. I saw Daisy's face, I saw my face, and then I saw BB-8 (the Star Wars drone).
"I was like - I'm in Tokyo, I've never been here in my life. But to have my image here and Daisy's was a weird experience - especially as we're two proud Londoners."
Ridley, who plays Rey, recalled daydreaming about being on the side of a bus while she worked in a pub just two years ago.
She said: "I used to watch buses go past with posters on and I'd be like, oh that would be really cool.
"I said to John in LA, I can't wait - I hope I'm on a bus. But I've not seen a bus yet."
Fisher, who returns as Princess Leia in The Force Awakens, has had decades to get used to seeing her image on the film's merchandise.
She recalled the strangest Princess Leia product: "A shampoo bottle - because you can twist off your head."
She added: "And there's a marijuana strain called Princess Leia. Not for me - but I have friends."
Although the film has already screened in a number of countries, Abrams is still keen to prevent plot details leaking out.
Addressing film spoilers which are already online, the director said: "We live in the world of immediate information. This is no surprise and while I know that people feel a need, and actually entitled - they want to know, when they want to know it - I was very gratified to hear people say thank-you to Disney for not spoiling everything before it comes out."
He explained: "There's an interesting thing. Star Wars is so about inclusivity and connection, the whole idea of the Force.
"When I was 10 and saw the film, the whole idea of connection was actually happening in the theatre... There was something incredibly powerful about that communal experience. Which is of course less and less likely when we have these little objects in our pockets that connect us, and we feel connected, but we actually are more disconnected."
He added: "I'm hopeful that while there will be spoilers out there it won't detract from the hopeful thrill that people might have seeing this movie together.
"That's the thing that is the most depressing about having spoilers. They're called spoilers for a reason - they spoil the experience. You get there and it's just a confirmation of something that you already know."
Ford said he was "amazed" and "grateful" that details of the plot had been kept so quiet - and that no-one had really "spilled the beans".