Diane Sawyer Leaves World News, David Muir Will Anchor

George Stephanopoulos promoted to chief anchor

Diane Sawyer is officially stepping down from the leadership of ABC's World News franchise, and David Muir is stepping up. Starting Sept. 2, David Muir will become the anchor and managing editor of the ABC News's flagship broadcast, World News.

ABC News president and GMA maestro James Goldston was voluble on the subject of Muir's talents in a memo to staff earlier today. "He was the first American journalist to report from Mogadishu, Somalia on the worst famine of a generation and recently took our viewers into Iran, getting rare access to the streets of Tehran," Goldston wrote. "David has made his reputation reporting from the ground on every big story of recent times, and we know that when the big stories happen, wherever they happen, David will be there for us and our audience." He will continue to anchor 20/20 with Elizabeth Vargas.

Sawyer, according to the network, continues to work at ABC News where 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," Goldston wrote. "Starting this summer she will begin to develop these new stories […]."

Meanwhile, George Stephanopoulos is getting a bump up to chief anchor, driving live coverage. In the position, he'll continue to do a lot of the big stories he's been anchoring in the recent past, while continuing to anchor Good Morning America and This Week. "George is adept at balancing both complex global and public policy questions and deeply personal stories in interviews with numerous luminaries from Vladimir Putin to Angelina Jolie," wrote Goldston.

Stephanopoulos will lead the news division into the next two election cycles, as well.