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.
More top news
Super substitute Jill Scott marked her 101st international appearance with the winner as England squeezed past a stubborn Bosnia side
Conservative Party chairman Lord Feldman is being interviewed in an internal inquiry into bullying after the death of a young activist.
Former Davis Cup finalist John Lloyd led the tributes to Andy Murray, who ended Great Britain's 79-year wait for the famous trophy