Royalty and celebrities will be joining the expected 138,000 visitors descending on Blenheim Palace for the 50th anniversary Game Fair.

The event, opening tomorrow and continuing over the weekend, is the world's biggest sports exhibition and the national event for 50,000 owners of rural properties represented by the Country Landowners' Association.

On Saturday, the Duke of Edinburgh will be popping in to tour the show and also present long service awards to gamekeepers.

Among the many celebrities expected to attend are Elaine Page and Bernard Cribbins, who have set their sights on raising money for The Children's Trust in a charity clay pigeon shoot.

The Game Fair is returning to Blenheim after a four-year gap, with more than 1,000 exhibitors on 500 acres of parkland on the Duke of Marlborough's estate.

The core interests remain the long-established pursuits of shooting and fishing but organisers are laying on a range of new themes and interests.

Visitors will be able to check out the latest in country style clothing at a Fashion Showcase area.

There is also a feature marking the 50th anniversary, showing how things have changed since 1958.

Fair director David Hough said: "This is a fantastic celebration of the history of the Game Fair and a fascinating reflection of the way we were.

"But the 2008 Game Fair remains true to its roots of 50 years ago. It's a showcase for the rural ingenuity and enterprise that maintains the landscape, environment, habitat and social structures we all cherish."

Tickets must be bought at the entrance.

Friday's prices range from £58 for a family of four, to £25 for one adult, £24 for senior citizens and £8 for juniors (nine to 18), with younger children free. Weekend tickets are slightly cheaper. Gates open at 7am.