Lee claims that it is "essential" for the publisher to tell new stories set in the graphic novel's universe, while DiDio paid tribute to the creative team involved.
"One of the key characteristics of the comic book medium is that it is not brought to life by just one voice," Lee told Fast Company.
"These universes are developed and evolved by multiple creative voices, over multiple generations. The influx of new stories is essential to keeping the universes relevant, current, and alive.
"Watchmen is a cornerstone of both DC Comics' publishing history and its future. As a publisher, we'd be remiss not to expand upon and explore these characters and their stories. We're committed to being an industry leader, which means making bold creative moves."
DiDio added: "We sought out the very best writers and artists for Before Watchmen. This is a talented, fearless group who doesn't play it safe. They are the perfect fit creatively for this ambitious project."
Alan Moore, who created Watchmen with artist Dave Gibbons, has previously spoken out against the prequel project calling it "completely shameless".
> Alan Moore: 'There's no point in suing over Watchmen'
DiDio went on to pay tribute to Moore despite the writer's public criticism of DC.
"There's no denying that Alan Moore is a one of the great comic book writers. Dave Gibbons is one of the truly great artists in the industry," he added. "Neither of them are participating in Before Watchmen, but we appreciate Dave Gibbons's support.
"We know this project will be under the magnifying lens. Watchmen is a critical favourite, a cultural touch point. We believe when fans see the issues this summer, they'll be as excited as we are today."
Before Watchmen will consist of seven miniseries, featuring work from high-profile creators including Brian Azzarello, Lee Bermejo, JG Jones and J Michael Straczynski.
Move through a gallery of Before Watchmen cover illustrations below: