Christiane Amanpour is stepping down from anchor of “This Week.” (IDA MAE ASTUTE/ABC)

George Stephanopoulos, who hosted “This Week” before Amanpour, is returning to the program Jan. 8, while continuing to co-host ABC’s morning infotainment “Good Morning America.”

Amanpour will become a “global affairs” anchor for ABC in the United States and will anchor a weekday program for CNN International — a big player outside the United States in TV news.

This isn’t the first time Amanpour has served two networks at once. She was hired as a correspondent for CBS’s “60 Minutes” about eight years ago, while she also worked for CNN.

In a statement, Amanpour insisted Tuesday: “It’s been an incredible experience to have had a ringside seat to democracy in action at ‘This Week.’ It’s been an incredible honor to anchor such a prestigious program and I thank all of you who have helped me on that journey.”

Back in March of 2010, ABC announced that it had snagged the brightest star in the CNN firmament to take over as anchor of “This Week.” She replaced Stephanopoulos, who’d left the show to take Diane Sawyer’s place at “GMA” — after Di took over as anchor of ABC’s evening newscast when Charlie Gibson decided to retire.

In addition to anchoring “This Week” from the Newseum in Washington, Amanpour — one of the country’s most respected international correspondents — was also going to appear on other ABC News programs and platforms to provide international analysis of the important issues of the day.

“This is an opportunity to explain domestic politics and how it impacts the world,” she told Howard Kurtz — then writing for The Washington Post — when her appointment was announced. “I’ve always tried to make foreign news less foreign.”

And when it comes to international news, Amanpour had clout in spades. Queen Elizabeth II made her a commander of the Most Excellent Order of the British Empire in 2007 for her “highly distinguished, innovative contribution” to journalism. In 1998, Sarajevo named her an honorary citizen for her “personal contribution to spreading the truth” from 1992 to 1995, during the Bosnia war.

Washington welcomed Amanpour graciously, puzzling over what ABC News was thinking by hiring someone outside the box who had little knowledge of domestic politics to anchor “This Week.” (Amanpour is the daughter of an Iranian father and a British mother and grew up in both of those nations.)

CNN’s Washington-based media-show host Kurtz, now also Washington bureau chief of The Daily Beast and Newsweek, noted that she would be the first broadcast-TV Sunday Beltway show anchor with a distinctly non-American accent, and wondered whether the decision was foisted upon the news division by its Disneyland bosses (ABC is owned by Disney).

Meanwhile, The Post’s then-TV critic, Tom Shales, complained that interim “This Week” anchor Jake Tapper eased “quickly and comfortably into the role of ‘This Week’ host and became a kind of ‘favorite son’ …even as the clock ticked his interim tenure away and the Grand Duchess Amanpour approached on her royal barge from overseas.”

During her run on “This Week,” Amanpour averaged about 2.3 million viewers – virtually identical to the 2.35 million Tapper averaged during his term as interim host between Stephanopoulos and Amanpour.

In his final year hosting the gig, before migrating to “GMA,” Stephanopoulos attracted slightly more people: about 2.84 million of them.

But in the 11 weeks of this TV season to date, Amanpour’s numbers trailed those of NBC’s “Meet the Press (2.92 million) and CBS’s “Face the Nation” (2.86 million), which are battling for the lead.

“Face” has been winning the derby among the 25- to 54-year-olds who are the target audience of news programs; “Meet the Press” has the edge among total viewers. If “This Week” can return to its Stephanopoulos-era numbers, it, too, would become a first-place contender.

Now, word that Amanpour was on the outs had been in the water for a few weeks and first surfaced several days ago in the New York Post’s Page-Six gossip column. But Tuesday, an eczema of reports broke out after NYT’s media and Occupy Wall Street blogger/tweeter, Brian Stelter, accidentally tweeted to his 97,000 followers, including many of The Reporters Who Cover Television: “I’m hearing that Amanpour is formally out of ‘This Week’ — though only from a single source. Are you hearing same? 212-556-4668”

Moments later, Stelter tweeted: “Well, that was embarrassing. That was supposed to be a DM (direct message)”

Then he explained, in case anyone wondered: “I tried to send a DM about it, but screwed up. Sorry.”

Still later: “…now more sources are popping up…”

And then, another explanation: “3 reasons I don’t delete accidental tweet: people had already read it, some had retweeted it; it needed to be explained.”

And, before you knew it, Stelter’s Anthony Weiner Moment had been recast as some brilliant ABC News smoke-out.