Pixar has revealed Monsters Inc features a sneak preview of a character from its next film.
Executive producer John Lasseter says one of the characters in Finding Nemo makes a cameo appearance.
Eagle eyed fans will also spot a Jessie doll from Toy Story, and the caravan from A Bug's Life.
"So after Finding Nemo comes out then you'll watch the video of Monsters Inc and go 'Argh!' It's the longest we will ever wait for a laugh," said Lasseter.
"At Pixar we always kind of make movies for ourselves.
"We're adults, reasonably intelligent and we love to laugh, we love to be moved in an audience, we love to see action and so on and so that's kind of the approach we take with our films."
The voices in Monsters Inc are provided by John Goodman and Billy Crystal. Crystal was originally approached to voice Buzz Lightyear in Toy Story but turned it down.
Lasseter says his decision didn't affect the casting of the new film.
"Billy always says it is the one decision in his entire career that he regrets to this day making," he said.
"He said 'Yes' to this one before I'd even finished asking him. It's like he's trying to make up for lost time. He loves Monsters Inc, he's seen it probably six or seven times. He keeps bringing more and more people to see it."
Monsters Inc is out in the UK today.