Eileen O’Neill, the exec who stepped in and turned TLC into a powerhouse thanks to shows like “Jon and Kate Plus 8,” has been handed the keys to the Discovery Channel mothership as well.

As part of a massive executive restructuring unveiled Wednesday, O’Neill was named group president for Discovery and TLC, the flagship channels of Discovery Communications in the U.S.

Discovery Channel prexy-g.m. Clark Bunting remains but will now report to O’Neill. The move was one of several that will streamline the number of execs reporting into Discovery Communications prexy-CEO David Zaslav.

“Eileen is a homegrown Discovery talent with a 21-year track record of success that is nothing short of astounding,” Zaslav said. “Each network she led has been infused with creativity, innovation and content that breaks through the clutter of the television landscape.”

O’Neill has served as president and general manager of TLC since 2008. TLC chief operating officer Edward Sabin will now serve as interim g.m. of the channel and report to O’Neill as well. O’Neill will look to find a permanent g.m. for the channel.

According to channel insiders, Zaslav was looking at a way to reward O’Neill for her success at the company and also a way to play off both channels’ strengths. O’Neill’s double channel duty is now reminiscent of Bonnie Hammer’s long-held oversight of both USA and Syfy (and soon E!), as well as Nancy Dubuc’s recent promotion to overseeing History and Lifetime.

Meanwhile, Discovery also announced that Animal Planet prexy-g.m. Marjorie Kaplan will now serve as president of both Animal Planet and Science Networks. That means Science Channel g.m. Debbie Myers now reports to Kaplan.

It also means Bunting will no longer hold oversight of Science Channel. Under the previous setup, Myers reported to Bunting, but the channel will now no longer fall under the Discovery Channel wing.

Also, Investigation Discovery/Military Networks prexy-g.m. Henry Schleiff will now oversee Discovery’s Emerging Networks, Planet Green and Fit TV. As part of the change, Planet Green prexy-g.m. Laura Michalchyshyn will report to him.

Kaplan has served as prexy-g.m. of Animal Planet since 2007, recently overseeing a brand evolution beyond just animal programming. And Schleiff has been with Discovery since 2009, helping make Investigation Discovery the fastest-growing network in basic cable.

As for O’Neill, exec has brought TLC to new ratings heights thanks not only to “Jon and Kate” but also “19 Kids and Counting,” “Sister Wives,” “Sarah Palin’s Alaska” and “Cake Boss.” She returned to TLC after overseeing the launch of Planet Green and working as g.m. of Discovery Health.