Bill Weir, the co-host of "Nightline," is leaving for "another opportunity in the news business," said ABC News' president Ben Sherwood on Friday.
He did not say where Weir is going.
Weir, who has co-hosted "Nightline" since 2010, said on his Twitter account that he would be saying "goodbye" on Friday night's program.
Sherwood said that "Good Morning America" co-anchor Dan Harris will take over Weir's "Nightline" hosting duties, effective immediately.
Harris, who will continue in his post at "Good Morning America," joins Cynthia McFadden and Dan Abrams at the helm of the late-night news program.
Weir helped launch "GMA's" weekend edition in 2004 and was named co-anchor of "Nightline" in 2010.
"Bill’s style is singular; his voice unique; and we will miss him and, yes, his turkey frying safety tips," Sherwood said in a statement."