The Duke of Cambridge came face-to-face with one of Prince George's dream projects on Tuesday - a life-size Lego model of a new McLaren's supercar.
The Prince took a break from parental duties with a tour round the automotive company's high-tech design and production centres in Woking, Surrey, where chief executive Mike Flewitt introduced him to their newest road vehicles.
William was clearly awed by the 280,000-Lego-brick version of McLaren's new 720s road car, and said: "Wow! My son would love this!"
He added: "My son's very into Lego and he'd love this: it's incredible!"
But the Duke was also treated to a grown-up view of the real version of the car, and took a seat behind the steering wheel to test out its interior controls.
"I am a car enthusiast," he said. "I don't know very much about cars, but I like speed."
But when it came to finding out about the gadget-filled dashboard William made it clear what his customer priorities would be.
He asked: "The key question is: does it have a coffee cup holder? It's a fast car," he joked, "but does it have a coffee cup holder?"
In a comprehensive tour of the the site's innovative design area and production floor, the Duke was also given the opportunity to put the finishing touches on another model of the £210,000 720s, fitting its iconic badge to the front bonnet.
However, he admitted he was not quite sure of his sticking abilities.
He said: "Someone's going to be driving along and it's going to come flying off!"