The Queen met the England rugby team on Monday

The operation follows a similar one on the Queen's right knee in January.

A Palace spokeswoman said she would spend Christmas with her family at Sandringham as usual.

"The Queen is expected to leave hospital some time during the weekend and she should be fully active again within a few weeks," she said.

The Palace said Friday's surgery had been arranged following her first knee operation in January and was not the consequence of a fall.

The operation will take place at the King Edward VII hospital in London.

Cancellations

BBC correspondent June Kelly said the Queen, who is 77, has enjoyed very robust health during her life.

"At the beginning of this year when she came out of hospital, she did look as if she was having a few problems, but she looked in fine form the other day when meeting the rugby players."

A planned investiture ceremony at the palace, which will see England rugby hero Jonny Wilkinson receive an MBE, will go ahead as scheduled on Wednesday, but two other public engagements have been cancelled.

They are a carol concert hosted by the Women's Royal Voluntary Service (WRVS) on Thursday in London and the re-dedication ceremony of HMS Invincible in Portsmouth on Friday.

The Duke of York will attend the latter event instead of the Queen.