Britney Spears’ kid sister Jamie Lynn made an appearance on “Oprah” in 2002 that changed her life. Paula Kaplan spotted her on the show and flew the 10-year-old from Louisiana to L.A. for a sit-down.

“We asked Jamie Lynn if she had any characters,” recalls Kaplan, recently promoted to executive VP of talent and West Coast general manager for Nickelodeon. “She did an incredible old-lady security guard, and we were like, ‘That voice came out of this little body?'”

Kaplan cast Spears on “All That,” an established sketch comedy series featuring Amanda Bynes, and auds quickly confirmed her hunch about Spears’ star potential.

“Somebody sent me an email saying Jamie Lynn got the second-most fan mail after Amanda Bynes,” Kaplan says. “I thought, ‘We’ve got something here.'”

A 13-year Nickelodeon vet, Kaplan has overseen the casting of the network’s top stars, including Bynes, Emma Roberts, Drake Bell, Josh Peck, Lil’ JJ, Lil’ Romeo and Nick Cannon. Once she’s signed a performer, she monitors the child’s progress and his or her fan base. Kaplan often makes swift recommendations to the network: Give this kid a show.

Spears graduated to “Zoey 101,” a popular Nick sitcom which producer Dan Schneider created with the actress in mind.

Kaplan’s success with kids’ casting results from a combination of easy people skills (she started as PR director of Nick), business savvy and natural maternal instincts. After a certain amount of camera testing, Kaplan, a mother of two, sits down with each potential Nick hire.

“I want to be in a room with the kid so I can really engage with them and hear how they answer questions — without the manager or the mother,” says Kaplan, who also co-exec produces the Nickelodeon-sponsored Kids’ Choice Awards, an event frequented by such hugely popular teen stars-turned-megacelebrities as Justin Timberlake and Tom Cruise.

Kaplan is credited with raising the net’s corporate profile, forging and maintaining relationships with studios and making the awards show a high-profile Hollywood event.

Recent breakthrough: Found stars for “Drake and Josh,” “Zoey 101,” “Ned’s Declassified,” “iCarly” and “Just Jordan,” to name a few.

Role model: “Nick Cannon. He’s a really good kid. He’s driven, but he’s socially conscious. You don’t see Nick in the tabloids.”

What’s next: “We’ve entered into a record deal with Sony. On Oct. 9, our first CD, the soundtrack from the first season of ‘The Naked Brothers’ Band’ comes out. It’s ‘Monkees’ meets ‘Hard Day’s Night.'”