CHARLES Bronfman and his wife, Bonnie, are inviting 100 of their friends to an elegant evening of cocktails for what they hope will be a once-in-a-lifetime event.

The occasion? Their pending divorce.

The event isn’t likely to approach the extravagance of their wedding party less than three years ago, when they invited 200 guests to a seated dinner at the Four Seasons restaurant in the Seagram Building. The first-time bride wore an off-white, long silk gown by Angel Sanchez, and guests danced to the music of Peter Duchin.

Still, the party has engraved invitations with a request for business attire and an effusive statement about the couple’s affection for each other. It is signed, “Fondly, Bonnie and Charles.”

Some of those invited have found the whole idea odd.

Mr. Bronfman, the former chairman of the Seagram Company, and Mrs. Bronfman, an architect, explained that their “friendship is stronger without being married” and that they wanted to thank their friends for the support. On the invitation, they wrote that they looked forward “to continuing these relationships with everyone.”