Singer Katy Perry will make a guest appearance in
in a special live action episode which will see the animated characters turn into puppets.
The usually animated characters - which include Homer, Bart and Lisa - are to appear as puppets in a segment of the episode, which will air in the US Dec 5.
Perry will be seen playing the girlfriend of a cantankerous bartender named Moe, reports
The 25-year-old singer, who shot her scenes this September, will be joined in the episode by TV host Martha Stewart, who will appear as a cartoon version of herself.