London (CNN)Britain's Queen Elizabeth took part in supermarket retailer Sainsbury's 150th birthday celebrations on Wednesday, and even took the time to learn about self-service checkouts.
Staff demonstrated the checkout, now a ubiquitous sight in shops in many countries, to the British monarch, although she didn't have a go at using it herself, CNN affiliate ITV reported.
However the Queen gamely joked around with staff, asking them if it was possible to cheat the machine.
The monarch was on a tour of a replica 1860s-style Sainsbury's supermarket in Covent Garden, London, near the retailer's first shop on Drury Lane.
The original store stocked only the basic essentials, specializing in butter and eggs, but Sainsbury's is now a multi-million pound business.