It’s official: Kiran Chetry and John Roberts, who have been at CNN one month and one year respectively, are the co-anchors of CNN’s slipping “American Morning” starting April 16.

Soledad O’Brien and Miles O’Brien, unrelated except for having co-anchored the three-hour program CNN considers its flagship morning show nearly four years and nearly two years, respectively, are to become “featured special correspondents.”

“I’ve admired John’s journalistic chops since we worked together at CBS more than a decade ago, and it’s not surprising that he’s now recognized as one of the premier broadcasters in the business,” CNN/U.S. President Jon Klein said in the announcement Wednesday. “As for Kiran, we’ve watched her light up the screen for years, and we are thrilled that she was able to join our team. She’s a breath of fresh air and a delight to work with, and it’s no wonder she’s already been embraced by CNN viewers.”

“American Morning” has, since August 2006, dropped from a high of 510,000 viewers to an average of 375,000 in March, when “Imus in the Morning” on MSNBC averaged 353,000, according to data from Nielsen Media Research.

While the two shows jockey for second place, Fox’s “Fox & Friends” ranks first.

Mr. Roberts joined CNN in February 2006 after 14 years of hard news coverage he had hoped would make him Dan Rather’s successor as anchor of “CBS Evening News.” Instead, CBS went with long-time “Today” star Katie Couric. At CNN, Mr. Roberts has won fans as senior national correspondent and anchor of “This Week at War.”

Ms. Chetry joined CNN in February after being cut loose before the end of her contract at Fox News Channel, where she co-anchored “Fox & Friends” weekend editions and “Fox & Friends First” on weekdays. She has popped up as anchor on a number of CNN programs, including “American Morning.”

Ms. O’Brien, who was co-anchoring “Today” weekends at NBC when CNN hired her, will immediately join “CNN: Special Investigations Unit,” reporting in-depth on significant stories domestically and internationally. She will anchor and report hour-long specials throughout the year, as well as filing special reports on important ongoing and breaking news stories across all major CNN programs.

She has reported from the scene of a number of hot spots, including New Orleans after Hurricane Katrina and the tsunami that hit Southeast Asia in 2004.

She also anchored and reported a “CNN: Special Investigations Unit” hour built around Martin Luther King Jr.’s previously unseen private writings, notes and teachings.

“We are thrilled to be able to match Soledad’s passion and reporting instincts with our desire to create more long-form, investigative journalism,” Mr. Klein said. “She is the perfect person to lead our national coverage of major news stories and provide in-depth investigative reports that are the hallmark of CNN.”

Mr. O’Brien, who was CNN’s space and aviation correspondent before moving from Atlanta to New York for “American Morning,” will become chief technology and environment correspondent.

“As viewers’ concern about the environment and fascination with technology grows, there is no better guide than Miles O’Brien to separate fact from fantasy,” Mr. Klein said. “He lives and breathes this stuff and is able to explain these pressing subjects in a way that captivates and informs Americans at a critical moment in our history.”