The couple were described as "prominent and much-loved" figures in their community.
Mr Johnson, elected as council leader earlier this year, had helped organise the town's Christmas market, launched at the weekend as part of a series of festive events.
On Friday he attended the opening of a Waitrose store in nearby North Walsham along with other signatories.
Mr Johnson's close friend, Benji Cabbell-Manners, had been away for the weekend and told the Eastern Daily Press of his "terrible shock" at hearing the news.
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A cool, largely clear night across the UK.