Matt Damon and Jessica Chastain attend The Martian premiere
Matt Damon, Jessica Chastain and Kate Mara were among the star-studded cast who dazzled on the red carpet at The Martian's European premiere in Leicester Square.
Oscar nominee Chiwetel Ejiofor also greeted the crowds and said he would have taken a different career path if he'd seen the science-fiction film, directed by Ridley Scott, as a child.
"I wish I'd seen this film when I was 13, I'd have been obsessed with it. I'd have set up a hub in my bedroom and driven everyone crazy," he said.
The Martian in the film's title refers to Matt Damon's character, Mark Watney, an astronaut presumed dead by his crew and left behind on Mars, who must find a way to survive on the inhospitable planet while Nasa and his former crew attempt to bring him home.
Ejiofor, 38, was among the actors who met real astronauts at the European Space Agency, while Damon and Chastain spent time with Nasa.
Ejiofor plays Dr Venkat Kapoor, director of the troubled space mission, and admitted, as one of the earth-based cast, that he was "jealous of all the people who got to fly out in to space".
The film, based on the best-selling novel by Andy Weir, has received high praise from critics - and it hasn't just been well received on earth.
Director Ridley Scott, famous for space-themed films from Alien to Prometheus, said he was pleased to have received a picture from the crew aboard the International Space Station, who were treated to a special screening of the film.
Scott said the audience would be surprised to find the film is "surprisingly amusing".
Asked what ISS crew members Scott Kelly and Kjell Lindgren thought of the movie, he joked, "I have a picture of them sitting there watching it. They weren't laughing."
House of Cards actress Kate Mara admitted that she struggled with the scientific knowledge required to play her character, computer scientist Beth Johanssen.
"I was definitely acting in this one. It wasn't a character I could relate to at all," she said.
The film has not convinced all the cast to immediately sign up to a commercial flight into space.
Kristen Wiig, who plays Nasa's head of public relations Annie Montrose, laughed that she'd turn down the chance "because I'd be nervous I wouldn't come back".
The Martian is out in cinemas on September 30.