Former Beatle Paul McCartney has filed for divorce from his second wife, Heather Mills McCartney, and she will in turn file counter claims in the case. British tabloid newspapers reported that McCartney, 64, had begun formal divorce proceedings this week, citing Mills' "unreasonable behaviour" for the break-up. McCartney's representatives were not immediately available for comment. A spokesperson for Mills, 38, said the former Beatle's second wife planned to file counter claims in Britain and the United States. The high-profile split was first announced in May. "Heather's going to be filing her own counter-claims about matters both in this country and America," said her spokesperson. "Any view she has on her divorce will be handled discreetly. She does not feel the need to repudiate claims she may be headstrong or feisty.