Pop star Madonna's and her husband, Guy Ritchie, are to divorce after nearly eight years of marriage.

A short joint statement read: "Madonna and Guy Ritchie have agreed to divorce after seven-and-a-half years of marriage, their representatives confirmed today.

"They have both requested that the media maintain respect for their family at this difficult time."

Film director Ritchie, 40, and Madonna married seven years ago at a lavish ceremony in Scotland.

But rumours have been circulating within the press that their relationship was increasingly under strain.

Madonna walked down the red carpet with Ritchie at the world premiere of his latest film in London's Leicester Square.

She made a surprise appearance at the event after the stars of Ritchie's film RocknRolla met with fans and the press.

Wearing a short black Stella McCartney dress with jewels down the front, the singer walked had walked arm-in-arm with Ritchie and posed for photographs.

Prior to the Leicester Square appearance, Ritchie had stamped on suggestions that his marriage was over with a public show of support at his superstar wife's 50th birthday party.

Madonna's mother-in-law, Lady Amber Leighton, told reporters at her west London home today that she would not comment on the report that her son had split from the pop star.

She said: "We are not talking to Press and we won't be all day."

Later, Mr Ritchie's father John and sister Shireen left the family home.

The father refused to comment, and his daughter said: "No-one has got anything to say."