Star Wars star Carrie Fisher has been taken to hospital after suffering a cardiac arrest on a London to Los Angeles flight, according to reports.
Celebrity news website TMZ said the actress was given CPR by passengers on board before the plane landed at LAX and she was taken to a nearby hospital.
US actress Anna Akana tweeted about seeing the 60-year-old, who starred as Princess Leia in the sci-fi franchise, fall ill.
She said: "Don't know how else to process this but Carrie Fisher stopped breathing on the flight home. 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."
Fisher has been on tour promoting her memoirs titled The Princess Diarist.
Star Wars actor Peter Mayhew, who starred as Wookie Chewbacca, alongside Fisher, tweeted to say: "Thoughts and prayers for our friend and everyone's favorite princess right now.. @carrieffisher"