US actress Debbie Reynolds, mother of Carrie Fisher, in hospital
Celebrity news site TMZ reported that she may have had a stroke.
The Hollywood screen legend, 84, is best known for her starring role in 1952 musical Singin' in the Rain, alongside Gene Kelly.
Fisher - renowned for her role as Princess Leia in the Star Wars series - died on Tuesday following a cardiac arrest on a plane.
Ms Reynolds posted a statement about her daughter's death on Facebook on Tuesday: "Thank you to everyone who has embraced the gifts and talents of my beloved and amazing daughter. I am grateful for your thoughts and prayers that are now guiding her to her next stop."