The magazine has been given a simpler layout. New features include: a 20-page style section; Now What's On with TV, film and music recommendations; and Now You, a 13-page section devoted to health, real life, travel and food.
The new-look Now will also push readers towards the website, as well as draw content from the website, such as the daily polls, which will be used in the Now Votes section.
The staple celebrity photos and stories will remain a feature of the magazine.
Johnston said: "The Now brand has fantastic heritage and we're enjoying ourselves more than ever."
In the last ABC magazine figures, published in February, Now magazine's circulation fell by 6.5% year on year to 540,132, making it the fourth-biggest celebrity title, behind OK!, Heat and Closer.
New ABC figures are due to be published on Thursday.