Billy Crystal has revealed how excited he was to explore the back story of Monsters Inc in the Pixar sequel to the animated hit.
Monsters University joins huge fluffy blue monster Sully and his small green one-eyed pal Mike as they are starting out at the prestigious School of Scaring.
Billy Crystal, who voices ambitious bookworm Mike Wazowski, hit the blue carpet at the world premiere of the film in LA and revealed the chance to go back in time opened up more creative options.
"I was excited because it opened up more possibilities. Most people expected us to follow Boo, they wanted to see little Boo again but that was too obvious.
"Peter Pan went back to find Wendy and she was 45 and having hot flashes and that wasn't good. This gave us new possibilities of who these guys were, we could create a new life for them."
More than a decade has passed since the first Monsters movie hit the big screen and Billy said he still feels a great deal of affection for his pea-shaped counterpart.
"He's got courage, he's got intuitiveness, he's got fortitude and he believes in himself."
The new movie shows Mike and Sully meeting for the first time and how it takes a while for their relationship to grow. The When Harry Met Sally star said this was particularly affecting.
"They really respect each other and really know there is somebody good in there. In this movie they are trying to figure themselves out and they become very devoted to each other which I find very moving.
There are a couple of scenes where I think, "wow it's an animated movie they are making me cry and that is pretty great".