Arnold Schwarzenegger surprised the child stars of Kindergarten Cop by showing up in a Zoom reunion they were having.

Five of the actors who appeared in the hit 1990 comedy gathered on the video platform to celebrate its 30th anniversary.

To their surprise, Schwarzenegger himself showed up at the end of the conversation, leaving them open-mouthed.

“Are you serious?” Miko Hughes asked in the exclusive clip from Yahoo, adding: “I would have never expected this.”

Schwarzenegger – who plays a cop who goes undercover as a nursery teacher – proceeded to ask them all what they’re up to now.

Adam Wiley revealed that he’s still an actor as well as a world-champion magician.

Schwarzenegger told them: “Without any doubt, it was the performance of you kids that really made this movie. That’s what made it endearing. That’s what made it successful, and people wanted to watch it over and over again.”

He then revealed the context behind the film’s most famous quote: “It’s not a tumour – it’s not a tumour at all.”

Schwarzenegger said: “There were certain lines that, because of my accent, the kids were laughing. So I would just scream, ‘It’s not a tumour!’ and the kids would be laughing instead of being scared."

"[Director] Ivan [Reitman] told me, ‘If the kids are laughing at the way you sound, then I think the audience will laugh, too. And this is exactly what happened.”

Last week, Jumanji child star Bradley Pierce revealed how Robin Williams defended him and Kirsten Dunst from producers’ demands on set.