NEW YORK -- Charles Gibson said goodbye to "Good Morning America" on Wednesday, surrounded by his family and Kermit the Frog.

Gibson has been doing double duty for weeks, working the morning shift at "GMA" that he has had on and off since 1987 and recently taking over full-time anchoring duties on "World News Tonight." After seeing "GMA" through month's end, Gibson is going full-time to "WNT."

"GMA" and ABC News threw him a big on-air party Wednesday, celebrating Gibson's nearly two decades of mornings. Attending were Gibson's family, including his wife, children and 3-month-old grandson plus Kermit the Frog, baseball legend Cal Ripken Jr., former ABC Newser Steve Bell and, of course, co-hosts Diane Sawyer and Robin Roberts.

"For 19 years, my mornings have been not just good, they've been great," Gibson told viewers at the end of the two-hour "GMA."

Bell toasted Gibson, who began his morning-show career in 1987 with Joan Lunden then left in 1997 for other ABC News assignments. But after "GMA" ran up on the rocks against "Today," Gibson and Sawyer returned in 1999 and came tantalizingly close last year to unseating "Today" before the gap widened.

Gibson said that he cared more about Sawyer and Roberts than anyone else in this business.

"I didn't know Diane very well when we started our temporary gig here. I just knew I loved her as a broadcaster," Gibson said. "I came quickly to love her as a person. And Robin is an American original who we knew from the day she walked on the set, would fit right in."

Gibson joins an evening newscast scene that, like the mornings, has changed rapidly in the past few months. "NBC Nightly News" remains on top in total viewership but, for the past two weeks, was edged out by Gibson's "WNT" in the demo. CBS, while still in third place, is destined to challenge both with the September arrival of Katie Couric.

Couric and Brian Williams offered taped congratulations to Gibson in his move from morning to evenings, with Williams wishing him limited luck.