Chris Pratt claims his ''natural instinct to be a goofball'' nearly wrecked the 'Jurassic Park' series.

The 36-year-old actor stars as dinosaur researcher Owen Grady, who specialises in the behaviour of velociraptors, in the franchise's latest instalment 'Jurassic World', but admits his tendency to be ''goofy'' meant he had to undertake a ''little ritual'' before every scene.

He told Entertainment Tonight: ''For me, the biggest challenge is to not be goofy, because it's my natural instinct to be a goofball.

''Before every take, I would have to do this little ritual to be like, 'Don't turn into a dumbass halfway through this take!'''

And Chris - who has three-year-old son Jack with wife Anna Faris - recently admitted he won't pinch himself because he's scared of ''waking up'' from his whirlwind success.

He shared: ''I don't pinch myself because when you pinch yourself, it's to see if you're dreaming and it'll wake you up.

''Being part of a movie that was essentially my 'Star Wars' ... it was like my first event movie, I saw it in the theatres, it blew my mind! I was 13 years old, so to be in that is crazy. It's just crazy.''