He will feature in a film being made to celebrate this year's 70th anniversary of Royal Windsor Horse Show.
Cllr Rayner, whose family owns Berkyn Manor Farm in Horton, was one of five people intimately connected with the world famous show who were followed by the cameras.
As the Mayor of Windsor and Maidenhead this meant being recorded at some exciting royal events, including the recent state visit by the president of the Arab Emirates.
Colin, who hands over his mace and chain of office to a new mayor Cllr Andrew Jenner next Tuesday, said: "My company has handled the grass cutting and maintenance at the horse show since the 1970s, so they asked me to be one of the five pivotal characters in the film.
"I was not that keen. But my daughters were competing in the show this year, so it was nice for them to be involved."
Colin's 15-year-old triplets Alice, Isabel and Victoria are already showing signs of becoming talented riders.
Colin also agreed to be interviewed briefly by BBC America in the Guildhall for a feature on 'royal baby mania' in Windsor - but admits he was very guarded.
He said: "The time to celebrate babies is when they have safely arrived. I said everyone wished the Duchess of Cambridge well and was praying for her."
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The Met Office has issued a yellow alert for Windsor and Maidenhead, Slough and Wokingham, warning that rain moving eastwards across the south of the country may turn to snow in some places.