Elizabeth Taylor is in hospital in Los Angeles.
A publicist for the actress said she "entered the hospital for a routine visit and is doing fine".
The spokesman said she was well enough to be posting messages on Twitter, with which she had "fallen in love".
No further details were given about her health, where she is being treated or when she would be released.
Last year the actress spent several weeks in a Los Angeles hospital but little detail was given about her state of health.
Publicist Dick Guttman previously dismissed reports she was seriously ill. He said the stories were "dramatic, overstated and untrue".
Taylor, 77, who uses a wheelchair, has suffered from a number of health problems in recent years.
The BBC reports they include a hip replacement in 1995 and surgery to remove a brain tumour in 1997.
She has broken her back five times and has the brittle bone disease osteoporosis.
Born in London, Taylor first achieved stardom aged 12 in National Velvet.
She later won Oscars for her roles in the 1960 film Butterfield 8 and Who's Afraid of Virginia Woolf?
She was made an honorary dame by the Queen in 2000.