Nickelodeon is doubling down on iCarly and Victorious crossover spinoff Sam & Cat.

The kids cable network has greenlighted 20 more episodes of the top-rated comedy led by Jennette McCurdy (iCarly's Sam Puckett) and Ariana Grande (Victorious' Cat Valentine), bringing the first season's total count to 40, The Hollywood Reporter has learned exclusively.

Sam & Cat, created by veteran comedy producer Dan Schneider, follows Sam and Cat as they become best friends and unlikely roommates who start a babysitting service. The June 8 series debut was Nickelodeon's biggest live-action launch in three years with 4.2 million viewers. The expanded order comes after only four episode airings.

"It's a very tall order but it also feels great. The show has been so well-received, and competition is greater than ever these days. Making a hit show is even more challenging today than, say, 10 years ago," Schneider tells THR. "It's a little daunting to do 40 episodes in your first season, but what makes it fun is the success, because we're all sharing in that."

For Nickelodeon, staying in business with Schneider is key, as he has produced seven successful shows (from Keenan & Kel and Drake & Josh to iCarly and Victorious) for the network. "We're trying to keep our record of excellence going," Schneider says of his Schneider's Bakery production company's track record. "We wanted Sam & Cat to be popular and good and something we were proud of. We feel we pulled that off, and this is a big endorsement of that." Schneider deadpans: "It's nice not to bomb!"

Production on the initial 20-episode order wraps up in the next few weeks (Sam & Cat finishes episode 18 on July 12). After filming concludes on the first half, the writers' room will open up in early September for the second half of the season.

Upcoming guest stars on Sam & Cat include Laverne & Shirley's Penny Marshall and Cindy Williams in their first scripted TV appearance in more than three decades, and the return of Sophia Grace and Rosie of The Ellen DeGeneres Show.

Sam & Cat returns July 13 on Nickelodeon.

E-mail: Philiana.Ng@THR.com

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