Sawyer, Stephanopoulos and Muir take on new roles for ABC News

NEW YORK -- Diane Sawyer is stepping down as ABC's evening news anchor, with David Muir set to take over as her full-time replacement at "World News."

Sawyer will concentrate on interviews and specials, devoting her boundless energy to a team that will create and commission original reporting, big issues and grand ideas for all platforms.

"For many years to come, Diane will be a driving force at ABC News with her exceptional storytelling genius," ABC News President James Goldston said in an email. "She will create innovative television specials and events, and, of course, continue to conduct the biggest interviews with the most important and extraordinary people in the world."

Muir is familiar to "World News" viewers as a substitute for Sawyer and has traveled around the country for his "Made in America" series. He will take over as anchor and managing editor on September 2.

"For more than a decade, David has been front and center reporting on the biggest stories of our time, helping drive us forward with tireless dedication, hard work and good humor," Goldston said. "From Katrina to Egypt's Tahrir Square, from Fukushima to Newtown, David has carefully guided our viewers through tragedy and world events with his tough questions and trademark compassion."

Muir will continue to anchor 20/20 with Elizabeth Vargas.

Additionally, George Stephanopoulos will take on a new role as chief anchor for live news events.

"George brings to all our programs his tremendous intellect, competitive drive, unwavering work ethic and a laser-like focus that have played an essential role in our recent success, driving Good Morning America forward to #1 and leading This Week into its best competitive position in a generation," Goldston said. "He will continue to anchor both shows as he assumes this new and critical leadership role."