LOS ANGELES • Queen Elsa and Princess Anna accomplish several impressive feats in Frozen 2 - outrunning giant rock monsters, freezing the sea and uncovering mysterious family history.

But, perhaps most impressive of all, they do it while wearing pants.

What might seem like an insignificant quick change actually marks a major shift in the Disney princess canon, which almost never lets its heroines swap skirts for pants - with the exceptions of Princess Jasmine's billowy turquoise bottoms and Mulan's army uniform, though the latter is technically not royalty.

At last Thursday night's premiere of the highly anticipated sequel, the film's cast and creative team discussed the cultural impact of the sisters' new looks and how they transform the traditional Disney princess image.

"The princesses are all things, they're all times, they're all outfits," said co-director Jennifer Lee on the red carpet at Hollywood's Dolby Theatre.

"Everyone sort of represents when the film was made and what the film's trying to show. These two women I'm proud of. They are carrying the weight of the kingdom on their shoulders... So they're going to wear what's right for that, and I love that you can wear anything."

Frozen 2 follows Elsa (voiced by Idina Menzel) as she sets off on a journey to discover how she came to possess her icy powers, accompanied by her fearless sister Anna (Kristen Bell), ice vendor Kristoff (Jonathan Groff) and their trusty sidekicks, Olaf the snowman (Josh Gad) and Sven the reindeer.

Along the way, the gang must depend on one another as they encounter dark forces at play in the enchanted forests and seas beyond Arendelle.

"This time, they didn't have to flee their kingdom in the wrong dress very fast," said Ms Lee, who is also chief creative officer of Walt Disney Animation Studios. "They had a chance to choose and of course you're going to wear pants when you hear the words 'enchanted forest'."

Producer Peter Del Vecho added: "They're going on a big adventure... It's going to be very physical, so it makes sense."

American actress Evan Rachel Wood - who voices the sisters' mother, Queen Iduna, in flashbacks and has been known to defy red carpet expectations with pant ensembles of her own - sees the updated costumes as a natural evolution informed by changing societal norms.

"They've done a really amazing job of still keeping the Disney feeling that we love, but just with a more modern feel," Wood said.

"The girls are still beautiful and still women, but they're just able to do a lot more now that they're in pants."

Their modernised outfits are part of a growing trend for Disney, which has also dressed Elsa in pants on Broadway and recently debuted a new and improved Bo Peep, no longer encumbered by a stiff crinoline skirt, in Toy Story 4 (2019).

According to Mr Clark Spencer, president of Walt Disney Animation Studios, keeping up with the times remains a key goal for the company, whether that means turning a children's movie about talking animals into a commentary on race relations (Zootopia, 2016) or putting its heroines in pants.

"We always have to think to ourselves: Whatever we're putting into our films is representing the world today, as much as it may be set in different times," Mr Spencer said on the red carpet.

"So I think for (co-directors Lee and Chris Buck), it was the exciting thing of saying there is more than one way to be a princess." DPA

• Frozen 2 will be released in Singapore next Thursday.