Diane Sawyer Says Farewell to "GMA"

Celebrating Walter Cronkite: Diane Sawyer
ABC's Diane Sawyer says goodbye to "Good Morning America" on this week after 2,881 shows - not that she's counting.

Sawyer announced on Monday's show that her last day will be Friday. It will give her one week off before she switches to the evening, taking over as anchor of ABC's "World News" for the retiring Charles Gibson on Dec. 21.

The "Good Morning America" stint was probably some 2,700 shows more than she expected. With the show in serious ratings trouble a decade ago, Sawyer and Gibson agreed to a temporary stint as co-anchors. Things went so well they agreed to stay on indefinitely, and Robin Roberts replaced Gibson when he went to "World News."

The show was already in nostalgia mode on Monday, showing a clip of Sawyer driving a car and using red lights as mere suggestions, as colleague Chris Cuomo put it.