George Stephanopoulos has been designated the primary sub for Diane Sawyer after she takes over World News next year from Charles Gibson, an ABC source confirms.
In addition, This Week host and Chief Washington Correspondent Stephanopoulos will also team with Sawyer on special-event coverage.
Stephanopoulos was named chief washington correspondent in December 2005. He began hosing Sunday public affairs show This Week in September 2002, which last August beat NBC's iconic Meet the Press in the ratings for the first time in a decade.
Before that, he was the former top advisor to President Bill Clinton, as an ABC News correspondent, having joined ABC News in 1997 as an analyst for This Week.