LONDON (AP) _ The high society wedding Saturday of Viscount Althorp and former model Victoria Lockwood will bring Prince Charles, Princess Diana and an irresistible fund-raising opportunity to a quiet village church.

The vicar doesn't plan to beg from the distinguished guests, but the press will be invited to help preserve the 13th century church associated with George Washington's ancestors.

''I've organized a darling little girl from the village with a bucket, so you can give a donation to the church restoration fund when you park your cars,'' public relations worker Carole Adams told the press at a pre-wedding briefing.

Organizing one girl with a bucket was the least of the preparations for Britain's wedding of the year, which will unite Viscount Althorp, 25-year-old brother of Diana, the Princess of Wales, and Miss Lockwood, 24, a former model from the west London suburb of Barnes.

Six pews were removed from the church to accommodate the 12-piece chamber orchestra and the choir from Magdalen College, Althorp's Oxford alma mater. The 50-minute afternoon ceremony is the biggest event the Rev. Norman Knibbs has seen in his 10 years at St. Mary's.

''Although the archbishop of Canterbury is conducting the service, I will be there with a clean surplice and say a few prayers,'' said Knibbs, who added that he had seen Charles, Viscount Althorp, at church ''from time to time.''

St. Mary's, with its tall beacon tower, has been the church of the Spencer family - Princess Diana's family - since 1508 when Sir John Spencer bought the 15,000-acre Althorp estate.

Laurence Washington, the great-great-great-grandfather of the first American president, was a cousin by marriage of the Spencers and lived on the estate until he died in December 1616 and was buried in the chancel near the church altar. Laurence's younger brother, Robert, also is buried in the church.

Their tombstones bear the Washington coat of arms with three stars over two horizontal bars. Knibbs said it is thought to have inspired the design of the American flag.

''We are hoping to sell sponsorship of replacement stones for $120 to the many Americans who come by the church to see the Washington graves after visiting the Althorp house, which is open to the public,'' the vicar said.

''Each year the moisture gets in and freezes, making the stones crumble and flake off,'' he explained.

So far, Knibbs has collected $400 of the $190,000 needed to preserve the church, which holds 300 people and overlooks the thatched roofs and farmlands of Great Brington, 66 miles northwest of London.

The Daily Telegraph estimated the wedding, reception and dance will cost $155,000. Althorp, who was nicknamed ''Champagne Charlie'' by the tabloids during his university years, is a correspondent for the NBC program ''Today'' and heir to an estimated $80 million fortune, including the Althorp estate.

He proposed to Miss Lockwood in July after a six-week romance.

Prince Charles, Diana and their oldest son, William, are attending the wedding service. Their younger son, Harry, will serve as one of two page boys who will wear costumes reproduced from an 18th century Joshua Reynolds portrait of an earlier Viscount Althorp, John Charles, as a little boy.

The two bridesmaids' cream silk and chiffon dresses were copied from an 18th century Thomas Gainsborough portrait of another Althorp ancestor, Lady Georgiana Spencer.