Why is the Cookie Monster on a John Lennon song?

[rubbergenius]

Listening to the excellent John Lennon album Plastic Ono Band I've always wondered why during the lovely second song Hold On you can clearly hear the Cookie Monster (of Sesame Street fame) say 'Cookie'. Any ideas why Lennon added this to such an otherwise nice, laid back song?

[Ouisch]

That was John imitating the Cookie Monster.  "Sesame Street" was a relatively new TV program at the time, and Lennon was an avid TV watcher. 

[rubbergenius]

Thanks for that!