The 93-year-old actress - who returned to Ronald Reagan UCLA Medical Centre after suffering two blood clots following hip surgery - has seen a minister to receive the Christian prayers given before death, while her husband Fredric von Anhalt is keeping a bedside vigil.
Her publicist John Blanchette said: "Actress Zsa Zsa Gabor has seen a priest and is not doing very well. She`s in serious condition. She asked to see a priest and receive her lastrites.
Her husband, Frederic von Anhalt is at her side. It is a very difficult time for her family."
Zsa Zsa went into hospital last month to have hip replacement surgery, after she fell out of bed trying to answer the phone while watching the TV show `Jeopardy`.
She was partially paralysed in 2002 following a car accident, and her health has been troublesome ever since.
Despite being born in Hungary, Zsa Zsa made her name in Hollywood movies, starring in classics including `Moulin Rouge` in 1952 and `Touch of Evil` in 1958.