The occasion was the 2nd SWIFT International Tournament (1986) -- Karpov, Korchnoi, Timman, Miles, eight other players -- and I was invited to the opening ceremony at the Sheraton Hotel next to Place Rogier in downtown Brussels.
For some reason totally out of character, I had the foresight to bring along a copy of Jan Timman's book 'Art of Chess Analysis'. I must have known that Timman would be playing in the tournament and would be at the opening ceremony. During the cocktail portion of the reception, I asked the Dutch GM if he would autograph the book, which he did without saying a word.
As Timman was there with his wife, I asked her if she would also sign the book. She declined, I insisted, she declined again, and I asked once more. I was probably lucky that the GM didn't just tell me to get lost, but the third time she signed it. A scanned copy of the two signatures is shown below, Timman's above his wife's.
Later I discovered a photo of the couple in the January 1986 edition of Europe Echecs. It accompanied a report on the Timman - Tal tiebreak match for the 1985 Montpellier Candidates Tournament, so I suppose the photo was taken at that time. The photographer was the same Catherine Jaeg that I featured earlier this year in Black and White Passion (February 2016). I found another photo of the couple in a post on Alexandra Kosteniuk's blog: RIP Hans Suri and Lucio Barvas (June 2013), 'Hans Suri in 1985 sitting next to Jan Timman and Timman's wife.'
Please don't get the impression that I'm an autograph collector. Along with the Korchnoi and Timman(x2) signatures, I have Karpov's autograph on 'Chess at the Top 1979-1984', which I procured at the same SWIFT tournament. His third title match against Kasparov was due to start in a few months, so I said politely, 'I hope you win against Kasparov'. He answered, 'So do I.' And that was that. No more autographs.