The setting: London, late November, 1951. Joan Fontaine and the rest of the Ivanhoe cast and crew were almost finished with filming in London's MGM stuido. It had been a 5-month long shoot. Joan couldn't make it back to the United States for Thanksgiving, so she celebrated in London, and invited some friends over, including actress Mary Martin who was appearing onstage in "South Pacific". Martin, 4 years older than Joan, seemed to dominate the evening.
Here's how it went, in Ms Fontaine's own words. (Excerpt from her 1978 autobiography, "No Bed of Roses")
As we were shooting Ivanhoe in late November, I could not get home for Thanksgiving with the children. Therefore I arranged with the service kitchen at Grosvenor Square to prepare a real American Thanksgiving for a few of my friends. Mary Martin and her husband, Dick Halliday, were staying at the Savoy Hotel during her highly successful run of "South Pacific", so I invited them, as well as the cast of Ivanhoe.
Although I had stressed that the gathering was to be very informal, and I was in slacks, Mary Martin arrived in a black-cut velvet Mainbocher. Mary took over. Standing in what is called in the theatre "fireplace center," she directed us all, the conversation, even tow here we should sit at table. As the Hallidays left that evening, Dick said his thanks with "We had a nice time. Not very nice, but nice."
--From the book "No Bed of Roses" (1978)