Johnson, who captained the English rugby team to victory at the World Cup last November, will appear in the ads with the slogan "Boring? Who's laughing now?"
It is part of a seven-year campaign by Leicester Shire Promotions, which began with teaser posters last year that featured disparaging comments about the city like "Leicester! -- Nothing to shout about".
A life-long resident of Leicestershire, Johnson said he was immensely proud of the place.
"The city has undergone many transformations during its long history and has many strengths. The county is already known as a sporting capital but I believe it has the capacity to surprise many people with the range of what it has to offer and will become known as one of the key places in which to locate one's business and enjoy a good quality of life," he said.
The marketing initiative is being backed by local businesses, the county's three universities and public sector agencies. This year has been designated Taste Leicester, with a series of themed years being planned.
Johnson is also captain of the Leicester Tigers. He is widely expected to announce his retirement from international rugby this week.
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