With its bubblegum pink trappings, it is easy to underestimate the musical Legally Blonde. However, at its heart, say its cast and director, is a story that tackles sexism and female empowerment.

The musical, based on the hit 2001 film of the same name starring Reese Witherspoon, opened in Singapore last week at the Sands Theatre at Marina Bay Sands.

The show, with music and lyrics by Laurence O'Keefe and Nell Benjamin, centres on Elle Woods, a bubbly sorority leader from southern California. Her dream future is thrown into jeopardy when her college sweetheart Warner dumps her for somebody "more serious".

To win him back, she gets into Harvard Law School ("what, like it's hard?"), but discovers along the way that law, not wifehood, might in fact be her true calling.

One might be disinclined to take seriously a show that opens with shrieks of "Oh my god, oh my god, you guys" and spins an entire number out of the "bend and snap", a flirting technique that Witherspoon immortalised in the 2001 film.

But director Jeffrey B. Moss, 73, says there is more to it than just cheerleading and chihuahuas.

"Legally Blonde has two faces - one which is silly, Valley Girl and fun; and the other, which is this story about female empowerment, about this entertaining young lady who fights prejudice and stereotypes. That makes it an interesting and difficult puzzle - the challenge is to keep all those things up in the air."

There is a moment in the show when Elle experiences sexual harassment from a male figure of authority - something which was already in the film 16 years before the #MeToo movement gained ground last year.

"That is a moment much like what is in the headlines," says Moss. "It's always been part of the story, but people come to it with a different perspective now."

American actress Maris McCulley, who plays Elle, says the role has made her a more confident person. She is able to laugh off otherwise mortifying mishaps, such as one time on tour in China, when she accidentally kicked a stiletto heel into the audience during the finale.

"Many women can identify with Elle in terms of being underestimated," says the 30-year-old. "It's rewarding to be able to portray that journey."

"You don't necessarily think about Legally Blonde bringing such a powerful message," says actress Mychal Phillips, 30, who plays Paulette, a hairdresser whom Elle befriends. "You come in for the music and the fun. It's an easy pill to swallow, but it's the perfect story to be telling today."

They share the stage with dogs which play Elle's chihuahua Bruiser and Paulette's bulldog Rufus. Working with them can be unpredictable - on tour, one sometimes refuses to do tricks, while the other has been known to randomly urinate on cast members.

"You're never sure what's going to happen," says Phillips. "It's exciting."

Correction note: This story has been edited for clarity.