Dame Elizabeth Taylor is to undergo heart surgery.

The Oscar-winning actress will be admitted to an undisclosed Los Angeles hospital to have an operation on a leaky heart valve and has asked her legions of fans to pray for her.

She wrote on her Twitter webpage: "Dear friends, I would like to let you know before it gets in the papers that I am going into the hospital to have a procedure on my heart.

"It's very new and involves repairing my leaky valve using a clip device, without open heart surgery, so that my heart will function better.

"Any prayers you happen to have lying around I would dearly appreciate. I'll let you know when it's all over. Love you, Elizabeth."

The 77-year-old screen legend - who was left devastated by the death of her close friend Michael Jackson in June - suffers from a number of ailments and is regularly seen being pushed in a wheelchair.

In May 2008, she was taken to a Los Angeles clinic, which her publicist described as a routine check-up.

Following her release, she wrote on her Twitter page: "Home from the hospital and feeling great."