Los Angeles: Star Wars actress Carrie Fisher has suffered a massive heart attack on a flight from London to Los Angeles, according to US media reports.
TMZ reports that doctors who happened to be on board performed lifesaving CPR on the 60-year-old, who is best-known for playing Princess Leia.
Paramedics attended to Fisher, with witnesses telling TMZ she looked unconscious and was wearing an oxygen mask.
Her brother, Todd Fisher, said the star was receiving treatment in an intensive care unit at UCLA Medical Centre.
He told Entertainment Tonight: “If everyone could just pray for her that would be good. The doctors are doing their thing and we don’t want to bug them.”
Actress Anna Akana was on board the flight and tweeted that Fisher stopped breathing “for 10 minutes or so”.
“Don’t know how else to process this but Carrie Fisher stopped breathing on the flight home,” she wrote. “Hope she’s gonna be OK.
“So many thanks to the United flight crew who jumped into action, and the awesome doctor and nurse passengers who helped.”
Fellow passenger Brad Gage said he was “in complete shock” after the incident.
He tweeted: “I don’t know what happened. Not really sure what to do right now but I hope she is ok. I hope she is ok.”
A source told the Los Angeles Times that Fisher was “in a lot of distress on the flight”.
A spokeswoman for police at LAX airport said: “Los Angeles police responded at 12.15pm to Terminal 7 regarding a female victim who went into cardiac arrest.
“Upon arrival the LAFD (Los Angeles Fire Department) was already performing CPR on the victim and the victim was transported to a local hospital for further medical treatment.”
United Airlines issued a statement saying Flight 935 from Heathrow to Los Angeles was met on the ground by medical personnel after the crew reported that a passenger was “unresponsive”.
Mark Hamill, who played Luke Skywalker in Star Wars, wrote on Twitter: “As if 2016 couldn’t get any worse… sending all our love to @carrieffisher.”
Peter Mayhew, who is best known for playing Chewbacca, tweeted: “Thoughts and prayers for our friend and everyone’s favorite princess right now.. @carrieffisher.”
Fisher had been on a tour to promote her new book, The Princess Diarist. During her time in the UK she recorded an interview for The Graham Norton Show.
Norton wrote on Twitter: “carrieffisher Don’t even think about it!! This planet needs you on it! Sending so much love xxx.”
Fisher is due to appear in Star Wars: Episode VIII when it opens in cinemas in December 2017.
She was once married to the singer Paul Simon and has a daughter from another relationship, actress Billie Catherine Lourd.
The Star Wars star claims in her book that she had an “intense” affair with her co-star Harrison Ford during the making of Star Wars.
She is the daughter of singer Eddie Fisher and actress Debbie Reynolds.