'Toy Story 4' is probably one of the most eagerly anticipated films hitting cinemas this summer.

And it's funny too because 'Toy Story 3' seemed like such a perfect finale to that series. But if the critical reception - including our 4/5 stars review - is anything to go by, 'Toy Story 4' is an ideal encore.

The flick sees Woody, Buzz, Jessie and all Andy's - now Bonnie's - toys together again. They welcome new toy Forky to the mix. Meeting him soon leads the gang to head out on a road trip. Along the way, they meet old friends and make new ones.

It's supposed to be as tear-jerking as the last one. It's also in keeping to the recurring theme in the animated series as it explores what it means to be a toy.

As it turns out, 'Toy Story 4' was not a last minute add on. Rather, it was in the works before 'Toy Story 3' was even finished.

'Toy Story 4' director Josh Cooley and producer Jonas Rivera told ComingSoon.net:

"Andrew Stanton one of the writers, who’s written on all the Toy Story films, one of the godfathers of Toy Story, he actually started the outline for number 4 while 3 was still finishing. But he kept it secret. We didn’t know, I’m speaking for all of us."

In fact, at the time, the filmmakers were adamant that 'Toy Story 3' would be the final chapter in the series.

Rivera explained:

"We started to crack that open and go, 'What would happen if Woody did everything right, he survived it all, he landed on his feet with Bonnie?' And what we realized in that discussion was the end of 3 is really the end of Andy’s story, but the story of Toy Story is Woody...

"Like, what do you do when you’ve done everything right and your life’s not over? You have to reinvent yourself. And that was kind of the crack in the nerve, like okay, how would Woody do that? That was interesting to us."

The return of Bo Peep was  a key kickoff point to the fourth film.

Cooley said: "It had Bo returning. That was pretty much it.

"So it’s not like Andrew sat down, ‘I’m going to tell a story about being an empty nester,’ he just sat down like, ‘What if Bo Peep came back?’ That was it."