Diane Sawyer to Anchor ABC's "World News"

The President of ABC News, David Westin, has confirmed that Charlie Gibson is stepping down as anchor of ABC's "World News Tonight." He will be replaced by Diane Sawyer in January.

In a letter to staff, Westin announced the resignation and said it was Gibson's decision. He also praised the anchor's leadership in the past few years, which he called "difficult and turbulent" after the death of Peter Jennings in 2005 and the injuries to Bob Woodruff in 2006. Westin also announced Sawyer's new position.

"We are fortunate to have a journalist of Diane's proven ability and passion to step into the important position of anchor for World News," Westin wrote.

Gibson took over the anchor's chair in May, 2006 for Elizabeth Vargas and Woodruff, who left the co-anchor positions after Woodruff was severely injured by an improvised explosive device in Iraq. Woodruff and Vargas had been co-anchors since Dec., 2005 after the death of Peter Jennings.

In a letter to his staff, Gibson said he had been planning to resign from his job on Good Morning America when Westin asked him to anchor World News Tonight.

"It has not been an easy decision to make. This has been my professional home for almost 35 years. And I love this news department, and all who work in it, to the depths of my soul," Gibson wrote.