Singer Madonna (L) and director Guy Ritchie arrive on the red carpet at the 61st Cannes Film Festival May 21, 2008. [Agencies]

Madonna has reportedly hired the divorce lawyer who represented Sir Paul McCartney. The '4 Minutes' singer was said to be impressed by Fiona Shackleton's handling of the former Beatle's bitter battle with ex-wife Heather Mills and wants her to represent her case against Guy Ritchie.

A friend of the singer insists Fiona is the natural choice for Madonna, telling Britain's Daily Mirror newspaper: "Madonna always seeks out the best in whatever field she is interested in at any given time.

Fiona Shackleton is the best." Madonna - who reportedly has no pre-nuptial agreement with Guy - had been hoping to resolve their difference but has reportedly realised their relationship is irreparable, she needed a proper legal consultation.

One friend of the lawyer - who also represented Prince Charles in his divorce from Princess Diana - said: "Madonna was impressed by Fiona's work for Sir Paul and the way she handles herself in the public eye. She is a consummate professional."

Earlier this month, Madonna was forced to deny rumours she had been having talks with Nicholas Mostyn QC - the lawyer who represented Heather in her divorce from Paul.

Madonna's spokesperson denied those claims, but of the latest rumours would only say: "We are unable to comment on this." Madonna, 49, and Guy, 39, have a seven-year-old son Rocco and an adopted son David, two. Madonna also has a daughter, 11-year-old Lourdes, from a previous relationship.