The Sarah Jane Adventures. The series made its debut on CBBC in 2007, with viewing figures continuing to grow year on year.
The fourth series, set to air this autumn, will again star Elisabeth Sladen as Sarah Jane. Young actors Tommy Knight, Daniel Anthony and Anjli Mohindra return as popular regulars Luke, Clyde and Rani.
The new adventures will feature the usual mixture of thrills, scares and fun with enemies old and new, including the terrors of the Nightmare Man, the sinister Shansheeth, the series' first visit to an alien world, and even a dangerous journey back into history.
The series will go into production in Cardiff later this month with series three producer Nikki Wilson stepping up alongside Russell T Davies as executive producer and new producer Brian Minchin joining the team.
Damian Kavanagh says: "We are thrilled to be making many more episodes of The Sarah Jane Adventures.
"It is been a huge ratings and critical success on CBBC and we hope our viewers are going to be hooked on Sarah Jane's action-packed adventures for some time to come."
BBC Wales Head of English Language Programmes, Clare Hudson, says: "The idea for The Sarah Jane Adventures sprang from the success of Doctor Who and it has since rocketed in popularity in its own right, thanks to the vision, talent and hard work of the show's brilliant cast and crew."
The fifth series will go into production in 2011 for transmission later that year.