Disney Channel has picked up a second season of its animated preschool sleuth series “Special Agent Oso.”

Sean Astin lends his voice to the lead character on “Oso,” which the Disney Channel said is the fastest-growing preschool series ever for the cabler.

Riffing on classic secret agent movies, “Oso” revolves around a bumbling stuffed panda bear who works for UNIQUE — “United Network for Investigating Quite Usual Events.” Oso and his team help kids accomplish tasks such as using the library or cleaning their room.

Since its April 4 launch, “Oso” has been No. 1 in its 8 a.m. slot in the kids 2-5 demo, averaging 628,000 preschool viewers.

Walt Disney TV Animation is behind the show, which airs in 35 territories and in five languages, reaching a total of 23.7 million unduplicated viewers.

Ford Riley (“The Land Before Time”) created and exec produces; Jamie Mitchell (“Hey Arnold”) is director and co-exec producer. Show is produced with a mix of digital-cutout, 3-D and Flash animation, plus collage and papier-mache.