It’s nearly 20 years since Danny Wallace’s bestselling book Yes Man was turned into a movie starring Jim Carrey – but he can still remember working with the madcap Hollywood star.

“It was surreal,” says Danny, 49. “I never thought it was going to happen until I was on my way to the Warner Brothers studio and I realised I’d get to see him messing about in the flesh.”

Happily, Jim did not disappoint – as Danny discovered, when the pair spotted a tourist train going slowly past.

“I was like, ‘Shame for these people. All they’re seeing is empty brown buildings with nothing happening.’ And Jim just said, ‘Wait here,’ and then he ran and jumped on the train and started rocking it from side to side. It must have made their year.”