Take two of today's most bankable actors - Jennifer Lawrence and Chris Pratt - and put them together in a movie. Add elements of science fiction, romance and some thrilling action, and then watch as the electricity between the two charges the entire enterprise into a satisfying whole.

Passengers, which opens in Singapore tomorrow, is both a demonstration of good old-fashioned star power as well as genuine on-screen chemistry.

At 26, Lawrence is the highest-paid actress in the world, commanding US$20 million (S$28.9 million) for this film.

Her hits include the young adult fantasy adventure series The Hunger Games (2012-2015) and the X-Men superhero flicks (2011, 2014, 2016).

And Pratt, 37, is riding a hot streak that started with animation The Lego Movie and irreverent superhero movie Guardians Of The Galaxy in 2014 and continued with dinosaur thriller Jurassic World (2015), the No. 4 movie in the world on the all-time list with US$1.67 billion earned.

They are both passengers on a 120-year-long journey on board the Starship Avalon to a new planet and new lives.

He plays Jim Preston, a mechanical engineer whose hibernation pod malfunctions and wakes him 90 years too early. She plays Aurora Lane, a writer who also gets woken up in advance.

As they fall for each other, the ship begins to fall apart and they have to figure out why in order to save it.

A big reason the romance is believable is that Lawrence and Pratt hit it off right off the bat despite not having worked together before.

Speaking at the Park Hyatt Beijing last Saturday, she says: "I knew he was going to be funny, but he was the funniest person to ever live. It's true, I've met everyone who's ever lived. We became best friends immediately."

He adds: "Not dissimilar to chemistry as a science, you put two things that are naturally attracted to each other. When you put us together, we're like drawn to each other."

To which she responds: "I move towards you because I know you're gonna make me laugh."

Before his leap to big-screen leading man status, Pratt was known for playing the lovable and dim-witted Andy Dwyer in the sitcom Parks And Recreation (2009-2015). It is a role that he is still closely associated with as that character's goofiness and innate decency seem to emanate from the actor himself.

Even after breaking out in the movies, he remains humble and down-to-earth, a genuine nice guy who is always up for a laugh. He kept up a running joke on his Instagram account with a series of photos in which one could never see the whole face of his "bestie Jen".

They are very much at ease in each other's company at the movie junket and their mood is light despite the red alert for air pollution in Beijing. The toxic smog is probably the reason the red carpet event is being held indoors. It takes place just before the press conference, at which they graciously accept gifts of silk robes and stuffed panda bear figurines in space suits.

Their comfort with each other comes across in their banter as well.

When Pratt suggests that their closeness was fostered by people putting their chairs close together during filming, Lawrence says: "We would have been the same exact way if people weren't laying chairs out for us. I'm offended." Then she laughs.

It turns out that the laughter goes both ways.

"She cracked me up every single day and I don't laugh that easily actually. I'm usually the one making people laugh. That's something that will always draw me to somebody," says Pratt.

Chemistry, powerful as it is, does not take place in a vacuum. Lawrence points out that the script plays a big role in helping to generate on-screen heat. She adds drolly: "We're puppets really, we just follow whatever is on the page."

The script was penned by Jon Spaihts and was included on a 2007 list of unproduced high-value screenplays. His writing credits include the sci-fi film Prometheus (2012) as well as superhero flick Doctor Strange (2016).

More than a love story

The film was directed by Norway's Morten Tyldum, who helmed the feted historical drama The Imitation Game (2014), about the mathematician Alan Turing.

Pratt says: "What attracted me to the project was how original the story was and how daring and provocative the ideas were that exist inside the story. I loved the challenge that this poses to all audience members as they watch it, questioning themselves how they would react in this situation. It's really daring and thought-provoking."

While Jim and Aurora fall in love in the movie, it is also true that they were the only people awake on the ship. Lawrence, who had previously dated actor Nicholas Hoult, muses: "You can also ask the same question about any kind of love story. What if you hadn't walked into that coffee shop? What if you hadn't taken the same class as the man who became your husband? You fall in love with who is in your environment. That is just one of many controversial questions that the movie asks."

She also likes that the film does not spoonfeed viewers. "One of the characters in this movie does something completely irredeemable and you have the right as an audience member not to agree with it. I don't really see that in a lot of movies. I see a lot of movies telling you how to feel, who to like, who not to like."

She has certainly had a knack for picking projects. She is the youngest person to pick up four Academy Award nominations, winning once for playing a depressed widow in the romance Silver Linings Playbook (2012).

She tells The Straits Times that she would like to go behind the camera one day. "I've always loved film-making. I only got hired as an actor but as I'm working in films for 10 years, I'm learning as much as I can. I'm starting to only want to do projects now where I can be a producer so that I can have a little bit more control over what I'm doing."

She has co-written a script with comedienne Amy Schumer in which the two of them will star as sisters. Lawrence's list of upcoming movies include high-profile collaborations with Steven Spielberg for an adaptation of a photojournalist's memoir as well as with Darren Aronofsky (Black Swan, 2010) for the drama Mother, about a couple whose lives are disrupted by uninvited guests who turn up at their home.

The accomplished actress adds: "I don't think I'm ready to direct, I haven't learnt enough yet. You can't hide behind anything when you're directing."

As for Pratt, who has a four-year-old son with his wife, actress Anna Faris, he tries to straddle that sweet spot balancing work and family.

Next up for him is the highly anticipated sequel Guardians Of The Galaxy Vol. 2. He is not exactly repeating himself after Passengers though. As he puts it: "The only similarity is that it takes place in space."

Instead of varying his resume with smaller films, he says: "I'll probably do blockbuster movies as long as they let me, so that the other six months of the year, I can enjoy my life... taking my son fishing or spending several months at home nurturing my family.

"Some people live to work and I'm in a position to work to live."

•Passengers opens in Singapore tomorrow.

•Go to http://str.sg/4dTC to hear from actors Jennifer Lawrence and Chris Pratt on the difference between pretending to be asleep and playing dead.

•Love story in space, life story in New York