Archie will appear starting in series 2, which will air starting late 2010.
According to a press release:
|“||Archie (short for Archimedes) is a squirrel with a big bushy tail, bright eyes and cool glasses. With a signature phrase of "Sweetily deet!", he loves to learn new things, especially when it comes to counting and measuring. He is truly delighted to be friends with Potto and Hilda and loves the fact that every day in the Sesame Tree is filled with laughter, singing, learning and lots of silliness. Archie is like an adorable much loved little brother to Potto and Hilda. They encourage him to find ways to be less afraid if he’s frightened of something – or help him to prepare for a new challenge. The three friends are always looking out for each other. ||”|