Murder by Death (1976)

Maggie Smith, James Cromwell, James Coco, Estelle Winwood

Despite not knowing him, the world's most famous detectives can't pass up the offer of a "dinner and murder" invitation from wealthy Lionel Twain (Truman Capote). Each has no idea until their arrival at Two Two Twain who else will be in attendance. Those detectives are: amateur sleuths and New York