Both Kari and Oke were rescued as kittens and placed in the care of the Woodgreen Rescue Centre, Royston in Hertfordshire.
Oke was found abandoned in a bush and the staff of the centre set about the tricky task of trying to encourage Kari's mum to adopt Oke. Luckily, the plan worked and the pair became brother and sister.
Six weeks after being rescued they made their Blue Peter debut. They were named after John Leslie and Diane-Louise Jordan's Summer Expedition to Japan in 1991, where they performed karioke.
Kari and Oke were retired from the programme in 2004, shortly after they had their 13th birthday.