Oh, that one is too easy! It was all over the papers and tv at the time.
I couldn't remember the date so I got this from on-line:
In 1985 Prince Charles and Princess Diana visited the USA. During this trip a gala dinner was held for them in Washington, hosted by President Reagan and his wife Nancy. The dinner featured entertainment celebrities, which would have been ex film-star Ronald Reagan's way of hosting an event such as this. Bring on the equivalent of American royalty - entertainers! Guests included Eastwood, JohnTravolta, Tom Selleck and singer Neil Diamond as well as politicians and businessmen.
During the gala, First Lady Nancy Reagan took John Travolta aside and informed him that Princess Diana wanted a dance. He asked Princess Di to dance and they did.
The subsequent photographs of the glamorous Princess and romantic lead of such movies as Saturday Night Fever and Grease, made the front page of every newspaper and magazine in the world.
For John Travolta who had been experiencing the rejections of the film industry, this spot light on him and the fact that Princess Di would consider him important enough to wish to dance with him, revived his self-belief in himself. He attributes his resultant soaring film career to this moment in his life.
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OK, how about these two:
Burt Reynolds and Britney Spears