“She fell over in her home this morning and has been taken to hospital,” Annika Sönnerberg, a spokesperson for the Royal Court, told news agency TT.
Sönneberg said she could not speak about the extent of the princess’s injuries or where she was being treated.
“But she is doing well under the circumstances,” she added.
The princess underwent an operation last August after she broke her hip following a fall.
Princess Lilian, who was born in Swansea, Wales, married Swedish Prince Bertil, the king’s uncle, in 1976. The couple had met in London in 1943, where Lilian was working in a factory making radio antenna. Marriage was initially out of the question, as Bertil would have lost his right to the throne if he married a commoner.
The princess has carried out a wide range of public engagements, attending the Nobel Prize ceremonies and acting as patron of a number of organizations, although she has made few public appearances in the last two years. She lives in a house on Djurgården, in Stockholm.